Help/Advice Requested...humidity WAY too high...

[mkwelbornjr]

Hello, I am new to this forum. I would like to arm myself with as much info as possible before seeking help from our existing HVAC installer or someone else. We live in SC and are experience a very hot and humid time of year right now

We have two heatpumps for two halves of the house. The front half of the house sits over a garage and rooms. The heatpump is in one of the rooms. Humidity on this end remains around 45% which is okay I guess.

The back is the issue. The back sits over a decent sized crawlspace that is deep enough to breath, ventilated, and reasonable dry. The dirt around some edges near the foundation may be slightly damp but not much...the center is dry and cracked in some places. We do our best to keep standing water away from the house.

The RH in the back of the house is 50-63% which is high. We recently installed a decently powerfull Heil heatpump. In the winter it stank...like burnt dust or cigarette smoke...and at times fungus...but the air was REALLY dry. Now at this time...we can crank it down so much we literally freeze...but humidty hovers at 59%. I just went under to check out the system. There is some humidity dripping around the edges...but the drain line appears not to be clogged. I suspect the unit may not be 100% level, favoring the side away from the drip line.

Is it normal for there to be some dripping on the unit at the edges...and under some ducts when it is extremely humid. Or do we have a problem. The last unit rusted out for the same reason and we cant spare another $ for a new unit.

The people who installed it never seem concerned about humidity etc. Should we get someone to check the drip line and make sure the unit is level? The dust filters are the old Safgard type...the housing is rusty and was re-attached to the new airhandler unit. I pulled the filter out and sniffed around...the smell isnt there. What to do...its damp in the back of the house and the air coming out of the ducts stinks smells like gross wet air. Could there be condensation in the ducts? Any advice would be appreciated. Thanks!

[mchild]

Hello, I am new to this forum. I would like to arm myself with as much info as possible before seeking help from our existing HVAC installer or someone else. We live in SC and are experience a very hot and humid time of year right now

We have two heatpumps for two halves of the house. The front half of the house sits over a garage and rooms. The heatpump is in one of the rooms. Humidity on this end remains around 45% which is okay I guess.

The back is the issue. The back sits over a decent sized crawlspace that is deep enough to breath, ventilated, and reasonable dry. The dirt around some edges near the foundation may be slightly damp but not much...the center is dry and cracked in some places. We do our best to keep standing water away from the house.

The RH in the back of the house is 50-63% which is high. We recently installed a decently powerfull Heil heatpump. In the winter it stank...like burnt dust or cigarette smoke...and at times fungus...but the air was REALLY dry. Now at this time...we can crank it down so much we literally freeze...but humidty hovers at 59%. I just went under to check out the system. There is some humidity dripping around the edges...but the drain line appears not to be clogged. I suspect the unit may not be 100% level, favoring the side away from the drip line.

Is it normal for there to be some dripping on the unit at the edges...and under some ducts when it is extremely humid. Or do we have a problem. The last unit rusted out for the same reason and we cant spare another $ for a new unit.

The people who installed it never seem concerned about humidity etc. Should we get someone to check the drip line and make sure the unit is level? The dust filters are the old Safgard type...the housing is rusty and was re-attached to the new airhandler unit. I pulled the filter out and sniffed around...the smell isnt there. What to do...its damp in the back of the house and the air coming out of the ducts stinks smells like gross wet air. Could there be condensation in the ducts? Any advice would be appreciated. Thanks!


One thing you may want to investigate is the crawl space. The amount of moisture in the air is typically reported on a relative humidity basis, meaning relative to how much the air can hold. Warmer air can hold more moisture than cooler air.

When the warm moist air from outside migrates into your crawl space and meets with the relatively cooler crawl space air the relative humidity spikes way up - can easily reach near 100%. Anything over about 50 - 55% and you will have mold problems. You are already noticing the problems with moisture around the air handler unit (which I presume is located in that crawl space). The reason you are seeing moisture around the air handler is because it has cooler surfaces and the water is condensing out of the heavily moist air.

It is entirely possible that the increased humidity you have in that part of the house over the crawl is migrating in from the crawl. If there are leaks in your duct work (almost certain there is) it only makes it worse.

The best thing you can do is to close and seal off your crawl to the outside, place a heavy vapor barrier over the exposed ground, and install a dehumidifier to maintain the humidity at 55% or less. If you have lots of water getting into the crawl during wet periods you may need a sump pump too. It would also be a good idea to have you duct work sealed up too.

[mkwelbornjr]

Thanks. I was always told to make sure the crawl space has vents that open to let air flow through it? Which we have. Should I get the ducts cleaned? Or is that a total waste? What about a de-humidifer installed in-line with the ducts? The crawlspace is rather large and I think just sitting a dehumidifier out in the open would be like putting one outside.

[DLR]

First unit was probably oversized and if they replaced it with the same unit then it is oversized. Did anyone do a manual J load calculation. I know this gets repeated alot on this forum but it is necessary to control humidity problems. Also good advice from mchild.
You might want to invest in a UV light. You could also have a relay installed with a humidistat so your fan could swith to low speed to help with humidity control or you might could have the fan set to low speed it CFMs would still meet specs.

[mchild]

Thanks. I was always told to make sure the crawl space has vents that open to let air flow through it? Which we have. Should I get the ducts cleaned? Or is that a total waste? What about a de-humidifer installed in-line with the ducts? The crawlspace is rather large and I think just sitting a dehumidifier out in the open would be like putting one outside.

Keeping crawl spaces open had been the way of doing things for years. Some habits are hard to break, but the current building science is to close them and keep them dry so that you do not get mold that can not only destroy the wood framing of your home and also cause health issues for those that live in the home.

I live in the Mid-Atlantic area and my first home had sever damage from wood rot because of the moisture in the crawl. My current home has a 640 sf crawl with a height of about three feet. I am able to keep the humidity under 50% with a simple 50 pint dehumidifier. This summer has been especially humid and it still is off much more than on. The day I put it into place it was so humid everything in the crawl was wet as if a rain shower had just passed through. Once the humidity is brought below 50-55% the mold will stop.

Duct cleaning is generally not necessary - just get them sealed up properly using mastic and properly insulated.

A dehumidifier installed in line with the ducts would be a whole house unit and thus would be used to dehumidify the home but not the crawl. As evidenced by the comfortable 45% RH that you have in the other area of the home, a whole house dehumidifier is not necessary if you stop the infiltration of the moisture in the problem area. You could probably fix your crawl problem cheaper than having a whole house dehumidifier installed. In this case I think it would just be a band aide to the problem. You have already had to replace the air handler so unless the moisture is resolved that will still be an issue.

[wahoo]

I agree with the previous post that you need to cover the exposed dirt in the crawlspace with a moisture barrier (4 mil. plastic) and then install a dehumidifier if the crawlspace is still damp and moist. Oh yeah, you need to close off the vents to the outside if you want to dry out the space. These vents will allow moist outside air to come into the space, and make the pipes and un-insulated metal sweat really bad. Seal it up, and dehumidify it. You are getting moisture from the crawlspace into the HVAC system, and causing the back part of your home to have the higher humidity. In my opinion anyway.:)

[mkwelbornjr]

The fan speed makes sense. Can that be done on most modern Heil units? It is a big powerful air handler...but there are times when it runs for 30 min...we have the temp gradient set to 2. So it will be set on 68...go up to 70 and run until bag to 68.

Also, a few more details on the house. Built in 1979, cypress clapboard with the rmax foam behind it. Perhaps we need vinyl or hearty plank? Maybe moisture comes through the walls too.

Sealing off the crawl space is a good option. But there is still some damp soil around corners etc. And the entry door is a weak spot as well.



First unit was probably oversized and if they replaced it with the same unit then it is oversized. Did anyone do a manual J load calculation. I know this gets repeated alot on this forum but it is necessary to control humidity problems. Also good advice from mchild.
You might want to invest in a UV light. You could also have a relay installed with a humidistat so your fan could swith to low speed to help with humidity control or you might could have the fan set to low speed it CFMs would still meet specs.

[mkwelbornjr]

We paid Terminix $800 to install one. They just layed out lose pieces. They get knocked around and do not cover up to the edges. I assume a better job could be done with thicker plastic...anchored in place?



I agree with the previous post that you need to cover the exposed dirt in the crawlspace with a moisture barrier (4 mil. plastic) and then install a dehumidifier if the crawlspace is still damp and moist. Oh yeah, you need to close off the vents to the outside if you want to dry out the space. These vents will allow moist outside air to come into the space, and make the pipes and un-insulated metal sweat really bad. Seal it up, and dehumidify it. You are getting moisture from the crawlspace into the HVAC system, and causing the back part of your home to have the higher humidity. In my opinion anyway.:)

[DLR]

Yes if it is a PSC 3 or 5 speed motor. Make sure they check the superheat so there is no slugging of the compressor. I have personally never had duct sweating problems with ventilated or non ventilated crawlspaces but the systems are designed and set up right. I live in Alabama where high outdoor temps and humidity are high. I mastic my duct systems so they are tight. Let us know what helps your problem.

[teddy bear]

We paid Terminix $800 to install one. They just layed out lose pieces. They get knocked around and do not cover up to the edges. I assume a better job could be done with thicker plastic...anchored in place?

Were does the moisture come from? The moisture comes from the soil and outside air> Get the vapor barrier to the outside of the walls and get the barrier air tight on the earth. A little gravel on the plastic works. Close the vents to stop the wet outside air from infiltrating. Get a good dehu like a Santa Fe for just the crawlspace or Ultra-Aire for the whole house.
During hot weather, the a/c will handle the humidity in your home. To maintain <50%RH, during cool wet weather, you need supplemental dehumidification on the mainfloor and crawlspace. One small whole house dehu can handle the crawlspace and home.
Stop excess moisture from entering your crawlspace. Cooling your home to 68^F makes the exterior of your home a moisture condensing sweat ball. Moisture is condensing on all the cool surfaces. After you get your dehumidification in place, raise the inside temperature to 75^F, and set the dehumidifier to 45%RH. The stink will go away, you will save a lot of energy, and be more comfortable.
Regards TB

[mkwelbornjr]

Thanks for the help. So a whole house dehumidifier can dry air in the crawl space and inside the air ducts? We wont need but one unit?

[mchild]

Thanks for the help. So a whole house dehumidifier can dry air in the crawl space and inside the air ducts? We wont need but one unit?

A whole house dehumidifier will be plumbed into your existing duct work and will condition the air the duct work supplies and pulls its air return from. In order to use it to condition the home and the crawl you will need to put supply and return air ducts into the crawl. And at that point the completeness of the crawl space sealing becomes even more important as you do not want to be feeding air into or drawing air from a poorly sealed area (think of having your front door open). It will also require that you insulate the crawl to minimize heat transfer just as any other room in the home is insulated.

I think you will find the more economical approach that will reach your goal is to close off the crawl as reasonably well as can be done. Install the vapor barrier as discussed in this tread. Install sump pump if the crawl gets water into it. No matter the direction you go with dehumidifier these steps will be necessary. Then it comes down to the cost of the dehumidifier and what needs to be done to use it.

Going the whole house route will have a higher cost for the dehumidifier, plus you will have the cost of installation, plus you will have the cost of insulating the crawl.

Go with the small dedicated (like a 50 pint unit) and the initial cost is much less. There is minimal if any installation cost and the crawl does not need to be insulated.

Once you have reduced the source of moisture in the crawl (vapor barrier, sump pump, etc.) and then controlled the level of humidity of the air within the crawl space you will probably find that your home will have a reasonable level of humidity in the range of 45-50%. That is the goal, right?

If your air handler has a variable speed blower you can also have installed a t-stat that will bring on the a/c with reduced fan speed to function as a whole house dehumidifier. The Honeywell IAQ stat is a quality unit that will dehumidify on demand (meaning when there is not a call for cooling). My mother lives in the Charlotte area and can maintain 50% or less with a single stage a/c, variable speed blower, and the IAQ stat. She had the stat installed this spring and can not believe the difference in comfort.

[mkwelbornjr]

Thanks mchild! Its gonna take some time to implement these changes but we will go this route. I would hope the HVAC has a variable fan control. Its about a $ Heil Split System....N4H3 thru T4H4 are the series of numbers that describe the model #'s on the instruction manual the installer left us. I will have to check later as to the exact number. So if it is controllable...then we just need a different t-stat in the house that controls a bit more stuff? Right now we have a FAST 1 for ALL Programmable. Though the programming feature IMO is worthless. I wish you could just set the thing to run a long time but not freeze you out of the house. I did crank it down a good but. It gets to a point where the RH goes down..then goes back up. Whenever we turn the fan on without AC...of course RH skyrockets instantly.


A few notes about the crawlspace. In some areas the outside ground height is above the inside ground height by about a foot. but the brick is dry. However the ground right around the foundation on the inside is slightly damp...not wet...while the soil towards the inside of the crawl space is dry and cracked....which is great. We may just brick up the vents. Our builder installed them wrong anyway so you can't change them out. The house sits across the top of the vent...so it has to be cut out. They are worn and mice and bugs get in.

[beenthere]

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[mchild]

Thanks mchild! Its gonna take some time to implement these changes but we will go this route. I would hope the HVAC has a variable fan control. Its about a $ Heil Split System....N4H3 thru T4H4 are the series of numbers that describe the model #'s on the instruction manual the installer left us. I will have to check later as to the exact number. So if it is controllable...then we just need a different t-stat in the house that controls a bit more stuff? Right now we have a FAST 1 for ALL Programmable. Though the programming feature IMO is worthless. I wish you could just set the thing to run a long time but not freeze you out of the house. I did crank it down a good but. It gets to a point where the RH goes down..then goes back up. Whenever we turn the fan on without AC...of course RH skyrockets instantly.


A few notes about the crawlspace. In some areas the outside ground height is above the inside ground height by about a foot. but the brick is dry. However the ground right around the foundation on the inside is slightly damp...not wet...while the soil towards the inside of the crawl space is dry and cracked....which is great. We may just brick up the vents. Our builder installed them wrong anyway so you can't change them out. The house sits across the top of the vent...so it has to be cut out. They are worn and mice and bugs get in.



My crawl is similar in that the outside ground level is higher than the floor of the crawl. With a good rain I would have a foot of water in the there.

How wet does that soil get when you have rain? Down spouts from the house gutters should be so that the water is carried away from the foundation to keep moisture from sitting against the foundation wall and migrating through it. If the soil is not getting very wet during rain periods then most of the humidity is coming from the humid air. But the ground will always hold moisture so getting the vapor barrier over it will really help too. make sure the vapor barrier goes up the inside foundation wall (8 to 12 inches if possible) and is secured to the foundation with a good adhesive.

If the soil gets wet during rain then a sump pump should be considered. For that to work best a parameter drain will need to be dug just inside the foundation wall. The pump will then be installed at the low point of the crawl and the parameter drain is to pick up the water and carry it to the sump for the pump to then get it out of the crawl (all of this will be under the vapor barrier). Plus, with a sump pump, you will have a place to dump the condensate coming off the dehumidifier.

[teddy bear]

A whole house dehumidifier will be plumbed into your existing duct work and will condition the air the duct work supplies and pulls its air return from. In order to use it to condition the home and the crawl you will need to put supply and return air ducts into the crawl. And at that point the completeness of the crawl space sealing becomes even more important as you do not want to be feeding air into or drawing air from a poorly sealed area (think of having your front door open). It will also require that you insulate the crawl to minimize heat transfer just as any other room in the home is insulated.

I think you will find the more economical approach that will reach your goal is to close off the crawl as reasonably well as can be done. Install the vapor barrier as discussed in this tread. Install sump pump if the crawl gets water into it. No matter the direction you go with dehumidifier these steps will be necessary. Then it comes down to the cost of the dehumidifier and what needs to be done to use it.

Going the whole house route will have a higher cost for the dehumidifier, plus you will have the cost of installation, plus you will have the cost of insulating the crawl.

Go with the small dedicated (like a 50 pint unit) and the initial cost is much less. There is minimal if any installation cost and the crawl does not need to be insulated.

Once you have reduced the source of moisture in the crawl (vapor barrier, sump pump, etc.) and then controlled the level of humidity of the air within the crawl space you will probably find that your home will have a reasonable level of humidity in the range of 45-50%. That is the goal, right?

If your air handler has a variable speed blower you can also have installed a t-stat that will bring on the a/c with reduced fan speed to function as a whole house dehumidifier. The Honeywell IAQ stat is a quality unit that will dehumidify on demand (meaning when there is not a call for cooling). My mother lives in the Charlotte area and can maintain 50% or less with a single stage a/c, variable speed blower, and the IAQ stat. She had the stat installed this spring and can not believe the difference in comfort.

In your climate, with heating cooling ducts in the crawlspace, the duct leakage is enough that insulating the walls has a benefit. Whole house dehus need a small suppy 50-75 cfm of dehumidifiers output without a return to the dehu from the crawlspace. The return to the dehu should be from the open part of the home. After all the crawlspace vents are closed, you may need 60-75 cfm of fresh air to the home to purge indoor pollutants during the summer when homes tend to not breathe enough.
Mchild makes the argument that a 2 speed a/c with the right control is a whole house dehu. If you are getting any fresh air into your home and the moisture from occupants, with outside temps similar to inside, there is not enoungh sensible cooling load to remove the 30-75 lbs. of moisture per day to maintain <50%.
Well, this is an excellent chance to prove it. Keep us posted on how good maintaining <50%RH during wet cool weather works when there is no cooling load. You can always replace the residiential dehu that (if) does not do well in a cool crawlspace with a good whole house dehu later.

Regards TB

[mkwelbornjr]

Just so I understand everyone here. And I do appreciate this help! 1) I need to close the vents 2) gets someone really good to put a nice liner over the dirt...up the walls a bit...made of good strong plastic. 3) mount a normal dehumidifier in the crawlspace...just turn it on and make sure it drains in the right place. .... leave off the whole house unit for now 4) tryo to get a new tstate that will control the blower to have a slower mode to get RH down but not freeze the house to death?

I assume the humidity is high and the unit is sweating because of the high humidity getting pulled into the vents and up through the floor of the house right??

Also, The front unit keeps the front of the house...over basement rooms and a garage at 45%..even at the worst of weather. Which is great. But the one room that sits over the crawlspace...serviced by the front AC unit still smells like musty damp sewer-like mold. And of course the back over the whole crawl space smells the same. Its odd that the mold smell is worse late at night. It doesnt smell like mildew..but more like a sewer smell. Though it isnt sewer as our system is fine in regards to that.

So once I make these changes and reduce RH...what about the mold smell. Apparantly mold is still there. Where is it ... as I can't find the growth? Could it be just a small bit under the house that carries all over from the HVAC blowing it around? Could it be in the ducts? Is there any benefit to a duct cleaning? We built the house in 79...nothing has been cleaned since.

We did add a room in 2000 and they had to cut some new pipes in from the back system that is the problem area...ever since this point the smell got worse.

[mkwelbornjr]

after the hardest rain...the dirt nearest the foundation is maybe a dryish damp..if that makes sense. No running or standing water. We do have another area that has a white pipe with holes in it that comes in from along the front of the house. Apparantly there is a french drain across the front of the house with no gutters. I am suspicious that water is pulled under the house with this pipe..but its never more than just damp right in there. We could probably work on that pipe along with everything else.

One side of the house does get soggy in the grass area but we have added drains that seem to keep it dryer. All gutters are piped into the ground with PVC pipe...that is sealed...not the cheap flex pipe that snaps together...and clogs at every seem..if it stays together at all.



My crawl is similar in that the outside ground level is higher than the floor of the crawl. With a good rain I would have a foot of water in the there.

How wet does that soil get when you have rain? Down spouts from the house gutters should be so that the water is carried away from the foundation to keep moisture from sitting against the foundation wall and migrating through it. If the soil is not getting very wet during rain periods then most of the humidity is coming from the humid air.

[mkwelbornjr]

Sorry about that.

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[mkwelbornjr]

Just a short update. Today is sunny and hot. Air running in the back. But the RH in the house jumps to 62%. The highest yet. And its not quite as muggy outside as last week. The smell coming out of the vents is like dirty stale water...maybe like a wet dog...with some combination of mold. The thing that really bothers me is that it didn't always smell like this. We had a few vents added for the porch we glassed in around 2000. Maybe one of the new seems has come loose and is pulling humid air into the ducts and sweating. Befor 2000 we had a few mold spots on some walls but no smell coming out of the ducts.

[DLR]

If you have mold growing in your duct system it needs to be addressed. I
would recommend a new duct system externally wrapped. Also have your indoor coil cleaned.

Before you can lower the fan speed the crawl issues have to be addressed. Lower fan speed means colder air which would make the ducts sweat even more but if the crawl is right and the duct is properly insulated then you might meet target RH by lowering the fan speed either permanently of with a humidistat and possibly a freezestat. Maybe when the crawl is fixed and if the ducts stop sweating your RH might get low enough so do that first and then if you still have high RH have a tech check out the fan speed issues if any.

[mkwelbornjr]

We will address the crawlspace first. My concern is that if the ducts need to be raplaced...any liner installed will be damaged due to the work to remove and replace ducts. If we get the humidity down in the crawlspace...could the ducts just be cleaned and inspected to make sure they are sealed properly? The smell would make sense to be the result of sweating in the ducts.

[mchild]

We will address the crawlspace first. My concern is that if the ducts need to be raplaced...any liner installed will be damaged due to the work to remove and replace ducts. If we get the humidity down in the crawlspace...could the ducts just be cleaned and inspected to make sure they are sealed properly? The smell would make sense to be the result of sweating in the ducts.

If a 6 mil vapor barrier is put down it will be fairly heavy and will not get torn up very easily. And if you put a layer of gravel over it that will help protect it to. Finally, a good contractor will be conscientious about the work area and would stand behind the work and any damage that might occur to the work area. Just give them a heads up that you just had the work done (they will appreciate not having to work on the dirt floor) and ask that they be especially careful not to damage the vapor barrier.

[mkwelbornjr]

Thanks. I assume a good vapor barrier installer can work around the few pipes we have laying right on the ground. Incuding the line for the sprinkler system...and the coolant lines running from the unit to the outside compressor.



If a 6 mil vapor barrier is put down it will be fairly heavy and will not get torn up very easily. And if you put a layer of gravel over it that will help protect it to. Finally, a good contractor will be conscientious about the work area and would stand behind the work and any damage that might occur to the work area. Just give them a heads up that you just had the work done (they will appreciate not having to work on the dirt floor) and ask that they be especially careful not to damage the vapor barrier.

[mchild]

Thanks. I assume a good vapor barrier installer can work around the few pipes we have laying right on the ground. Incuding the line for the sprinkler system...and the coolant lines running from the unit to the outside compressor.

Sure, the goal is to just stop the moisture from getting to the air and then in the house and on the surfaces of the crawl so covering the dirt is the point. They may have to cut the barrier if there are any vertical obstructions, but then he will lay another piece over the cut with an overlap of a foot or more. Same on the seams of the different pieces that will be used - an overlap of a foot or more. He will also seal the seams of the overlap if he does it right.

[mkwelbornjr]

We are soon going to start this crawlspace project. But I still am concerned about the damp stinky air inside the back of the house over the crawlspace. It did not use to be like that. We even fixed the yard to drain standing water near the foundation, we glassed in a porch to keep rain from blowing in near the bedrooms. It should be drier than ever. But the smell has gotten worst in the past couple of years. The air blowing out of the furnace is putrid...not even like mildew but like dirty water with an algae or metal smell. I am not kidding. It almost gets worse everyday. We had the guys who installed the new unit come out and check it. The drain line was fine. They said it was sweating because it was so hot. Which I assume is normal...the unit is cold..naturally the surfaces will condense. They told use to turn the fan blower one to run the unit dry. Well of course the minute I turned the fan on and the RH in the house went to 68-70. So the fan went off immediately. Its blowing out unconditioned air so I expected that. I assume we need to have another hvac installer inspect the unit and ducts? I want to fix any underlying problems before encapsulating the crawlspace.

Also, could it be the crawl is not vented enough? Or would that just bring more humid air under the house?

We installed an irrigation system in 04. Could that be adding dampness in the crawl? I physically don't see it other than the dirt nearest the crawl door and that one side of the house being damper than the rest. But the sprinklers really don't shoot a river out of them.

Sorry to ask so much but either way we are looking at a large investment to fix.

[Shophound]

Venting a crawl space in a humid climate is just asking for trouble. Think about it...you're trying to ventilate a humid area with humid air...and then you stick equipment down there with exposed surface temperatures below the dew point of the air in the crawl space AND the air you're trying to ventilate the crawl space with - of course these surfaces will sweat!

Pertaining to your foul odor, does your air handler drain into a sanitary sewer or lift station? If so (or even if not), have your installer check that a) there's a trap on the a/c drain line, b) the trap is the correct type (not a running trap - waste of time and material), c) the air vent ( a tee in the plastic piping with a short section of pipe sticking straight up and the top open to the air) for the condensate drain piping is on the downstream side of the trap, not the upstream side.

You have a heat pump, and often installers get the condensate drain piping for heat pumps wrong. They either put too shallow of a trap in, or they put the right trap in but stick the air vent upstream from the trap, where all it does is suck in unfiltered air from the crawl space.

[teddy bear]

Also, could it be the crawl is not vented enough? Or would that just bring more humid air under the house?

Sorry to ask so much but either way we are looking at a large investment to fix.

Venting a crawlspace after plastic is laid down brings in more moist outside air and makes the moisture problem worse. Get the plastic down, close the vents and get a good dehumidifier in their.
Growing mold is a progressive process. It starts unoticed for a couple years and gets progressively worse over the years. Drying everything out is the first step. This includes wet ducts. A dehumidified crawlspace will not have sweaty ducts even with the a/c cold enough to dry the air in the home. The home will also need some dehumidification during wet cool weather. A good dehumidifier will keep both dry. Check out the Ultra-Aire for keeping both the home and crawl <50%RH. You will need a minimum of 90 pints per day capacity with +2,000 sqft. Regards TB

[mkwelbornjr]

From what I can tell...the drip line has the correct trap on it but I don't see an air vent. The drip line runs across the floor of the crawl to a drain pipe that runs inside the foundation from outside (it runs underground in front of the house under gravel and comes into the crawl where the house makes an L). There is often dampness around this pipe. I would think it needs to be removed.

In regards to Teddy Bear...would there need to be one dehumidifier in the crawl? Or one in the house too? Or are you talking about one built into the duct system?

[jmac424]

One of the problems I have encountered with home contractors is their inability to correctly size a HVAC system. Many times a system is oversized (more is better. If a system is oversized by putting in a 5-ton unit in a house requiring 3 tons of AC, the unit will cool the house too quickly, cycle too short, and fail one of it's main goals, to remove latent heat and humidity from the conditioned air space. This will result in high humidity and the old wet-socks smell caused by moisture and mold in the ducts.

[Shophound]

From what I can tell...the drip line has the correct trap on it but I don't see an air vent. The drip line runs across the floor of the crawl to a drain pipe that runs inside the foundation from outside (it runs underground in front of the house under gravel and comes into the crawl where the house makes an L). There is often dampness around this pipe. I would think it needs to be removed.

In regards to Teddy Bear...would there need to be one dehumidifier in the crawl? Or one in the house too? Or are you talking about one built into the duct system?

Is this pipe the condensate drain line empties into a sewer pipe or a french drain/storm drain pipe of some sort? If it's a sewer line and you see dampness around it, could be it is leaking and that may be one source of the foul odor you smell.

Question: do you smell the same foul odor in the crawl space as you do coming through the vents inside the house?

[mkwelbornjr]

How could we fix the issue if the unit is too big? The air in the crawl smells like dirt and dust but the air coming out the ducts smells sour. The front unit is just as big, smells fine, and RH up front is a nice 45%. The front is over a garage and garage rooms. But does have high ceilings.




One of the problems I have encountered with home contractors is their inability to correctly size a HVAC system. Many times a system is oversized (more is better. If a system is oversized by putting in a 5-ton unit in a house requiring 3 tons of AC, the unit will cool the house too quickly, cycle too short, and fail one of it's main goals, to remove latent heat and humidity from the conditioned air space. This will result in high humidity and the old wet-socks smell caused by moisture and mold in the ducts.

[jmac424]

How could we fix the issue if the unit is too big? The air in the crawl smells like dirt and dust but the air coming out the ducts smells sour. The front unit is just as big, smells fine, and RH up front is a nice 45%. The front is over a garage and garage rooms. But does have high ceilings.

The smell you get is not coming from your basement or crawl space. It's coming from inside your ducts and coil. Try a UV light installment, as someone suggested. But if your unit is oversized for the duct load on that system, the only cure is to replace it with a smaller unit or add more supply outlets. You should get a professional installer to run a heat load on your system. Your local power company may do that for you for free.

[mkwelbornjr]

Perhaps we could install some larger ducts to certain rooms that never got the correct air flow. That would help fix the problem and give some new ducts.

I have always heard that duct cleaning is a waste. Because any mold will die if you fix the root cause...

We do have the faint brown spots all over the walls in the back. You can hang a picture...and look under it a few years later and see spots. And you can even see those small book lice near the spots that eat mold. Its actually pretty disturbing.

Its my fathers house and the one I grew up in. I live here while I am getting a second degree. I feel it needs to be addressed. Of course my father can't smell or see any "problems."



The smell you get is not coming from your basement or crawl space. It's coming from inside your ducts and coil. Try a UV light installment, as someone suggested. But if your unit is oversized for the duct load on that system, the only cure is to replace it with a smaller unit or add more supply outlets. You should get a professional installer to run a heat load on your system. Your local power company may do that for you for free.

[jmac424]

Perhaps we could install some larger ducts to certain rooms that never got the correct air flow. That would help fix the problem and give some new ducts.

I have always heard that duct cleaning is a waste. Because any mold will die if you fix the root cause...

We do have the faint brown spots all over the walls in the back. You can hang a picture...and look under it a few years later and see spots. And you can even see those small book lice near the spots that eat mold. Its actually pretty disturbing.

Its my fathers house and the one I grew up in. I live here while I am getting a second degree. I feel it needs to be addressed. Of course my father can't smell or see any "problems."

Correct, cleaning duct systems, in my opinion, is a scam that needs to be addressed by the HVAC community. Larger supplies may help, such as changing a 4x12x7" to a 4x14x8", but the supply must be changed back to the trunk line. But this is useless if the trunk lines and the plenum, or the return, has been built too small for the unit.

[mkwelbornjr]

Is there some number or info off the unit or instruction manual that I can post here to tell you exactly what we have and then we will know for sure the size and all. I would say the back area is 1,000 sq ft. About 5 decent sized rooms and 2 long halls.

[Shophound]

Has anyone mentioned duct leakage yet?

If the return ducts that are in the crawl space are leaking, it will draw in moisture, dirt, dust, and odors from the crawl space. This dirt and dust will land on a wet cooling coil, and nearby surfaces inside the air handler and supply ducting adjacent to high relative humidity levels, creating a buffet for mold and mildew.

The air handler itself could be sucking in crawl space air. They aren't exactly the most airtight things ever built (although they should be).

Supply duct leakage- not good because it can depressurize the house, causing humid air from outdoors to be drawn into the house through cracks and gaps in walls, ceilings, etc.

Before I'd get all up in arms over equipment sizing, go for the low hanging fruit first. Duct leakage, condensate drainage, cleaning and sanitizing the cooling coil, blower wheel, and insulation lining adjacent to the cooling coil.

[mkwelbornjr]

Would any HVAC person be willing to clean the coil and blower wheel etc? And inspect the ducts? ...or do we need to hunt down someone special.




Has anyone mentioned duct leakage yet?
Before I'd get all up in arms over equipment sizing, go for the low hanging fruit first. Duct leakage, condensate drainage, cleaning and sanitizing the cooling coil, blower wheel, and insulation lining adjacent to the cooling coil.

[mkwelbornjr]

The furnace will run for a while if we put it on 67 degrees. The actual temp inside stays around 69. It will go off for a long time late at night and the RH rises to 62% in some rooms. It will start back up and lower the RH to say 54% but while its running the humidity then jumps back to 57%. It does run in long cycles. The stinky smell is more like sour clothes...like one smells when someone has been out in the hot sun...not sweat but just that sour smell clothes can get.

[Shophound]

What approximate area do you live? I only ask to ascertain your climate better.

Typically in winter, running the heat pump or furnace lowers indoor relative humidity levels. It's not because the heater "dries" the air. It is because typically outdoor air in wintertime holds a lot less moisture during cold weather than when it does during warm to hot weather. Should this air be drawn inside the return duct via leaks from an outdoor source, it will drive indoor humidity levels down. However, if this return duct leak is in the crawl space, that changes things.

Your odor resembles "dirty sock syndrome". Do a search on this site for discussion at length on this topic. It can be difficult to remedy, so be prepared.

[mkwelbornjr]

We live in upstate SC. We installed the new furnace last November. The indor humidty was low like 20-35% during heating season. Really dry for the skin but I can deal with that if it prevents mold from damaging antiques that we collect. However, the smell was almost worse after installing the new furnace and running the heat. Smelled like sour and cigarette smoke combined. Then that smell turned into the damp cold smell we have now.

[mkwelbornjr]

I am curious about adjusting this fan speed. Here is some more info about our HEIL system. The compressor is an R410A Split system heat pump.

The fan coils are labelled Heil FSU FSM FEM.
http://www.heil-hvac.com/products/fancoils.html I do see that on the Heil website it clearly states that on the FVM model one can adjust the fan speed to control humidity. Hoever it doesn't mention that on the model designation we have. But in the instructions for the FSU/FSM/FEM it says something about changing fan speed by connecting the wires to different poles. Would this be the same feature as on the FVM...or if not will it work to reduce the fan speed to dry the air better? If neither would work...could the model we have be modified to have the features of the FVM?

[mkwelbornjr]

As an addition to my last post, we have concluded that our new heat pump is not removing humidty as it should in hot damp temps. In some ways it seems to be worse than ever moving damp smelly air around the house. We have decided to do what it takes to fix this. We have a Heil unit. Should we:
1) Install a whole house dehumidifer?
2) replace the fan coils with a Heil FVM with variable blower for humidity control
would #2 work, would you need other parts...and would you need a new thermostat thatmeasures humidty and adjusts the fan speed?
3) Or should we replace the whole unit inside and out with a dual stage system and variable blower?

In addition to above we are going to cover crawl space etc.

Looking for some advice before we make the purchase.

[Shophound]

I would have all your ductwork that is in the crawl space leak checked before doing anything else.

Go for the low hanging fruit first...you might solve the problem that new equipment possibly would not.

[mchild]

As an addition to my last post, we have concluded that our new heat pump is not removing humidty as it should in hot damp temps. In some ways it seems to be worse than ever moving damp smelly air around the house. We have decided to do what it takes to fix this. We have a Heil unit. Should we:
1) Install a whole house dehumidifer?
2) replace the fan coils with a Heil FVM with variable blower for humidity control
would #2 work, would you need other parts...and would you need a new thermostat thatmeasures humidty and adjusts the fan speed?
3) Or should we replace the whole unit inside and out with a dual stage system and variable blower?

In addition to above we are going to cover crawl space etc.

Looking for some advice before we make the purchase.


You can do all that and maybe more, but i would not recommend it. The approach I would take would be to do one step at a time and let the results direct you as to what the next step(s) should be.

To me the logical steps would be to do the crawl space work and get that issue resolved to not only help with the HVAC and resultant comfort problem, but just as importantly, to resolve the overall problems that your home is having with excess humidity.

The next (or parallel issue) is making sure your duct work is completely sealed so that the leakage issues discussed here aren't continuing with this system.

Once the duct work has been properly sealed then you should look at having remediation for the coil and other areas inside the air handler for any mold issues that have started.

Finally, have a top notch contractor (not the installing contractor from what you have said) go over the system making sure you have proper air flow (it may be too high), refrigerant charge and such.

After all of this, if you are still having issues then consider replacement of components or adding a whole house dehumidifier. You may well decide some or all of that is no longer needed once the real problem is resolved.

The shot gun approach may get a lot of things done and nothing resolved. Come up with a plan and execute by hiring top notch contractors for each part.

[mchild]

I would have all your ductwork that is in the crawl space leak checked before doing anything else.

Go for the low hanging fruit first...you might solve the problem that new equipment possibly would not.


Shophound said in two sentences what I tried to say!!

[mkwelbornjr]

Thanks for the feedback. And I agree that is a logical sequence of solutions. I just focused on the unit itself because I keep hearing that new efficient units do not remove moisture well. And it seems the problem is worse with the new unit...and nothing changed in the crawl space.

Where on the unit would I look to see the tonnage to see if its oversized. The compressor is a Heil DX1400 H4H4300KC200 Space being served is about 2000 sq ft.

[beenthere]

Should be a 2.5 ton.

[mkwelbornjr]

Would this be printed on a label somewhere for me to verify? The part number would make me thinks its a 2.5 ton unit...though the last digits are gkc200 instead of gkd for the liste 2.5 ton unit.

The installers have an answer for everything but nothing gets fixed. Told us to just turn the fan on to dry the unit out and run it a few days. Yeah, instantly humidty jumps to 75% and it smells like a swamp. The crawl doesnt even smell that bad.

The owners manual for our unit also says..." if installed in damp area or crawlspace, arap coil unit in 1/4 inch insulation to prevent sweating" of course that has not been done.


Should be a 2.5 ton.

[beenthere]

Install manual

[mkwelbornjr]

I looked at it the other day and will check again in a few but the manual looked generic for several models. The manual for the compressor or under house coil/blower box? The tonnage refers to the compressor right? With the coil/blower being standard?


Install manual

[beenthere]

Install manual for the outdoor unit.

[mkwelbornjr]

Its definitly a generic manual that doesn't denote HP.

The unit does run a while at a cycle. It goes off for a while too. We have it set at 2 degrees differential. It stops in the early AM and the RH goes to 62%. I cut it down and after 2 hrs the RH was 59%...by night its 52%-53%. So IMO the unit is not removing all that much. If at the end we need to install a variable blower ...can a thermostat be installed that measures and controls temp and RH%?


Install manual for the outdoor unit.

[beenthere]

Yes. And the Honeywell IAQ thermostat is a good stat to use for it.

[mchild]

Yes. And the Honeywell IAQ thermostat is a good stat to use for it.

I think the OP said he does not have a variable speed air handler so the IAQ is going to be of limited benefit.

[beenthere]

I was answering this part of his question.


If at the end we need to install a variable blower ...can a thermostat be installed that measures and controls temp and RH%?

[mchild]

I was answering this part of his question.

And a good answer it was!!

[Shophound]

Thanks for the feedback. And I agree that is a logical sequence of solutions. I just focused on the unit itself because I keep hearing that new efficient units do not remove moisture well. And it seems the problem is worse with the new unit...and nothing changed in the crawl space.



Refresh my mind, please...the air handler section in your crawl space was not changed, only the outdoor section was?

[mkwelbornjr]

Bothe were replaced. New horizontal Heil air handler...of course the installer never listened to us about humidity issues and never mentioned a variable speed unit. They said the regular units run longer to remove humidity. And new outdoor compressor too. Both were from 1989 and needed replacing. The inside unit had rusted out. The new unit sweats and the heil manual recognizes that by saying to wrap insulation around it. That was not done either.

[Shophound]

Bothe were replaced. New horizontal Heil air handler...of course the installer never listened to us about humidity issues and never mentioned a variable speed unit. They said the regular units run longer to remove humidity. And new outdoor compressor too. Both were from 1989 and needed replacing. The inside unit had rusted out. The new unit sweats and the heil manual recognizes that by saying to wrap insulation around it. That was not done either.

Indoor unit was also changed - this leaves open the possibility that duct leaks that were not present with the old indoor section in place may now be there, thanks to the changeout from old to new. May not be the case for you but it's worth checking, on both the supply and return duct/plenum sides of your new indoor unit.

You will want to address the excess humidity issues in your crawl space regardless of what you have done to your a/c system. Why pay to dehumidify a LOT of moisture when you can install passive techniques that require NO energy beyond their manufacturing and installation processes, and will REDUCE the amount of moisture your HVAC system must remove for however long you stay in your house, and beyond.

[mkwelbornjr]

We will definitly do that. Most of the soil under there is dry...some is damp nearest the foundation. So I assume a good 20 mil sealed liner, wrapped up the walls would work.

I suspect a break in the ducts too. We can also smell the dirt under the house...and when the new heat pump turns on a distinct metal duct popping noise occurs...same when it goes off. As if someone is flexing sheet metal. We never heard that prior to installation.




You will want to address the excess humidity issues in your crawl space regardless of what you have done to your a/c system. Why pay to dehumidify a LOT of moisture when you can install passive techniques that require NO energy beyond their manufacturing and installation processes, and will REDUCE the amount of moisture your HVAC system must remove for however long you stay in your house, and beyond.

[mkwelbornjr]

This is an additional quick question seeking feedback. Something relevant but I forgot to mention. In 1989 we replaced old electrostatic filters front and back. We installed Spacegard filters...they slide out of a metal cabinet right where the return air enters the blower box. The filter was an accordian and fit over teeth...then you slid the frame back in place. The back unit has rust all over the sheet metal filter cabinet. The installers used the same filter assembly...replacing only the blower unit. However they removed the combs and now insert a filter preassembled in the shape of a box that fits snug in the area where the filter combs used to be. We replace it every 6mos. Could any problems be due to the filter design...rusting cabinet etc? I pulled it out and sniffed around...saw no issues except an inch of dust on the return air side...which I would expect.

[mkwelbornjr]

We have the HVAC guys up here today. We are going through a 3 step process to try and control humidity before trying other things. First, we have a 3 speed fan motor...going to slow it down. Second, if that doesn't work, we will install a new tstat that lets it run longer. Finally we will install a variable blower unit and proper hstat tstat to control it.

I did read in the Heil manual that the blower box should be wrapped in insulation if it sits under the house. We have never had that done.

[teddy bear]

We have the HVAC guys up here today. We are going through a 3 step process to try and control humidity before trying other things. First, we have a 3 speed fan motor...going to slow it down. Second, if that doesn't work, we will install a new tstat that lets it run longer. Finally we will install a variable blower unit and proper hstat tstat to control it.

I did read in the Heil manual that the blower box should be wrapped in insulation if it sits under the house. We have never had that done.
This good. Yes slow the blower max the moisture removal. New stat ok. New fan motor is big bucks without a total solution the moisture problem in a green grass climate. Put the VS money towards a 65-90 pint per day whole house dehumidifier. I got a VS motor and it helps very little. The whole house dehu provides <50% RH even without any cooling load.
In the end, you will need the wh dehu for real humidity control. Keep us posted. Regards TB

[mkwelbornjr]

Doesn't the variable speed with proper tstat work the same result as a whole house dehumidifier?

Would the whole house require any crazy duct work?? What moves the air through it when there is no cooling?

When we blow the fan only it smells warm and musty...I assume the wh dehum without cooling load would smell clean?



Put the VS money towards a 65-90 pint per day whole house dehumidifier. I got a VS motor and it helps very little. The whole house dehu provides <50% RH even without any cooling load.
In the end, you will need the wh dehu for real humidity control. Keep us posted. Regards TB

[teddy bear]

Doesn't the variable speed with proper tstat work the same result as a whole house dehumidifier?

Would the whole house require any crazy duct work?? What moves the air through it when there is no cooling?

When we blow the fan only it smells warm and musty...I assume the wh dehum without cooling load would smell clean?

These are all good questions.
The vs fan with an ideal t-stat operates to your normal settings until the temperature is satisfied. If your %RH is high at the end of cooling, the fan is slowed to a minimal temp and cooling continues until the %RH is satisfied or until the temperature in the home is 3^F below the t-stat setting. During cool, wet weather, you will be 3^F below the t-stat setting when the %RH is above the setting. Results is no cooling or dehumidification until the temperature rises. In a typical week of weather in WI, I have 0-6 hours of cooling per day. I get +20 lbs. of moisture from the a/c and +200 lbs. of moisture from my Ultra-Aire 65H whole house dehu. I keep the home <50%RH and the basement <55%RH. I am attaching last weeks data.
To eliminate the musty odor in my ducts (had dirty sock a couple years ago) I circulate the dry air from the dehumidifier through the a/c ducts throughout the home. Smell went away after the ducts dried out. If you have a crawlspace, I would treat it like I treat my basement. Plastic on the earth and close the vents, while maintaining <55%RH in the space using some of the dry air from the WH dehu. I also bring 60 cfm of fresh air 14 hours per day. I went from musty basement with dirty sock to fresh smelling home in 3-4 weeks. Its great.
My a/c salesman said I could pretty much control %RH with top brand VS a/c-furnace. When I explained what was happening, the salesman sent a teck out. The tech explained that the salesman did not totally understand the limitations of the system. He did what he could to slow the blower as much as possible. The a/c has a real cold coil but does operate enough during moderate weather.
That was a couple years ago. The fresh air was added to whole house dehu last year. Keep us posted on your results. I have yet to see an a/c that remove enough moisture during wet cool weather to maintain <50%RH throughout the home. Regards TB
http://www.ultra-aire.com/images/pdfs/UA-65_sheet.pdf

[mkwelbornjr]

Would the whole house dehum. have a fresh air intake on it? Is this how you bring the fresh air into your system? We have the installers ear on this so we need to be armed with info when talking to them. They did say they could leave the blower on a fixed slow speed but install some type of tstat that makes it run longer to lower RH. I assume this is one step down from both a RH controlling Tstate and a variable blower box. They also can install a UV light.

So we may get good results by installing simply the better tstat...leaving the unit as is on a fixed slow speed...and installing a whole house and drying up the crawl? Bringing RH from 55-62 down to 45-50??

As a side note...we have return ducts in several rooms....they are simply cut into the cavity of the wall with a hole cut out below and the duct picking up from there...so inside the vent area is simply wood and the back side of sheetrock. Is that bad?

[teddy bear]

Would the whole house dehum. have a fresh air intake on it? Is this how you bring the fresh air into your system? We have the installers ear on this so we need to be armed with info when talking to them. They did say they could leave the blower on a fixed slow speed but install some type of tstat that makes it run longer to lower RH. I assume this is one step down from both a RH controlling Tstate and a variable blower box. They also can install a UV light.
?
I bring the fresh via the WH dehu. For specifics, check the web address I posted previously. Leaving your a/c fan on a low speed will dryout the ducts but make your home %RH higher after the cooling cycle is complete. If your a/c is cooling for 30 minutes and not cooling for 30 minutes, moisture removal by the a/c will be dramatically reduced by fan "on" mode. Better to limit fan "on" to several hours during the day when the a/c is not cycling. An example is operating the fan "on" when the home unoccupied for 4-6 hours in the heat of the day. This would thoroughly dry out the ducts/coil everyday. Several hours before the occupants return to the home, the t-stat setting is lowered automatically lowered to desired late afternoon setting. Cooling the home down to desired temp causes several hours of constant cooling, which removes a tremendous amount moisture. Then during the evening hours, you return to the fan "auto" mode. This only operates the fan when the cooling coil is cold. Coil moisture re-evaporation back to the home is minimized. If you had a W H dehu, you would allow the dehu to maintain <50%RH when the a/c is unable to maintain <50%RH. Fresh air is an option during the times of the year that your home is not getting enough fresh air when the home is occupied. UV lites???? Get it writing and let us know how it works.






So we may get good results by installing simply the better tstat...leaving the unit as is on a fixed slow speed...and installing a whole house and drying up the crawl? Bringing RH from 55-62 down to 45-50??
?
Suggest setting the fan speed to optimize moisture removal. Drying the crawlspace will eliminate the duct sweating in the crawlspace and reduce the moisture level in the home. I would also allow the WH dehu to also provide dehumidification to the home for the times of year that a/c will not run long enough to remove the +200 lbs. of moisture per week. In WI that is most of the summer.




As a side note...we have return ducts in several rooms....they are simply cut into the cavity of the wall with a hole cut out below and the duct picking up from there...so inside the vent area is simply wood and the back side of sheetrock. Is that bad?
If you keep the crawlspace dry, the impact of leaky ducts is decreased. Any gross pressurization/depressuration causes uncontrolled movement of air. That is usually not good. A can of foam or caulk can fix alot of this.
Regards TB

[mkwelbornjr]

Thanks for the info. When you usually turn the fan one (when not cooling) it usually made the RH jump 10% higher...with smelly unconditioned air?? So the gist of things is to not replace the blower with VS and install a whole house dehum..which combined with current fixed slow fan speed should help?

What will happen come winter when heat is running? Will the slow fan be a problem? We had this new unit installed in November...during the cold of winter it would run all night. Even after it had been running a while we got a different kind of stinky smell...like burnt dust/cigarette smoke/musty...all combined into one. Almost burned your eyes. And it was extremely dry...whole opposite to what it is now...

UPDATE...We have been running with the slower fan speed all morning...RH may be down 2-3% but nothing dramatic. It is running non-stop as I assume it is taking longer to cool with the slower speed. We could change the tstat differentital to 1 rather than 3?




If your a/c is cooling for 30 minutes and not cooling for 30 minutes, moisture removal by the a/c will be dramatically reduced by fan "on" mode. Better to limit fan "on" to several hours during the day when the a/c is not cycling. An example is operating the fan "on" when the home unoccupied for 4-6 hours in the heat of the day. This would thoroughly dry out the ducts/coil everyday. Several hours before the occupants return to the home, the t-stat setting is lowered automatically lowered to desired late afternoon setting. Cooling the home down to desired temp causes several hours of constant cooling, which removes a tremendous amount moisture. TB

[teddy bear]

Thanks for the info. When you usually turn the fan one (when not cooling) it usually made the RH jump 10% higher...with smelly unconditioned air?? So the gist of things is to not replace the blower with VS and install a whole house dehum..which combined with current fixed slow fan speed should help?
?
Operating the fan with a wet coil will raise the %RH in the home until the coil dries. The residue in the ducts and on the coil will smell until it dries out and stops growing. If you had the WH dehu, you will be able to maintain <50%RH. Using the a/c ducts for dry air distribution, will slowly dry out the ducts between cooling cycles. If you are able to slow your fan enough to make the a/c a good moisture remover, there very little benefit in changing the fan to a VS fan. Have your a/c contractor slow you current fan to provide 20-25^F temperature drop of the air being cooled. Dryout your crawlspace so that the supply ducts to not sweat. P





What will happen come winter when heat is running? Will the slow fan be a problem? We had this new unit installed in November...during the cold of winter it would run all night. Even after it had been running a while we got a different kind of stinky smell...like burnt dust/cigarette smoke/musty...all combined into one. Almost burned your eyes. And it was extremely dry...whole opposite to what it is now...
QUOTE]
During the winter, operate the fan in a normal heating speed. You have so much dirt/mold in the ducts, clean or replace them. Keeping everything dried out stops biological grow that cause the odor. Have your a/c contractor confirm that you have a Merv 9 air filter inplace that does not by-pass air to keep the equipment clean. Get your contractor to fix the air leaks, get your air flow setup to remove moisture when cooling, seal your crawlspace from outside air leaks, and eliminate moisture evaporation from the earth. After all that, get a wh dehu to maintain <50%RH throughout, and add fresh air for summer fresh air ventilation. When the home dries out during cold weather, stop fresh air ventilation until spring.

[QUOTE=mkwelbornjr;4322912]
UPDATE...We have been running with the slower fan speed all morning...RH may be down 2-3% but nothing dramatic. It is running non-stop as I assume it is taking longer to cool with the slower speed. We could change the tstat differentital to 1 rather than 3?

Does this mean you have the a/c running all morning? If you have enough cooling load to run an a/c all morning, you should be removing a lot of water. How cold is the air coming out of the ducts to your home? Use the wider T-stat differential. You have a longer cooling cycle which improves moisture removal. As I said previously, longer cooling cycles remove much more moisture. Minimum cooling cycle should be +30 minutes. 10 minute cycles remove very little moisture.
Regards TB

[mkwelbornjr]

Here's the best way I can describe this. The tech slowed the fan yesterday morning to the slowest spead. The tstat was set on 68....house temp read 69. Ran for hrs blowing cold air out but only shut off after a long run. Did that a few times into the night. Got cooler at night so the unit turned off...and stayed off until 9am when I cut the tstat down a degree to get it to cycle on. At that time RH in the house was 61% in the back. It smelled wet and moldy/algae like. Once the air came down, RH went to 53% in some rooms and 55% in the middle room in the back of the house. Middle room is always the dampest..and oddly its over the dryest area in the crawlspace...ground so dry its cracked down there. So yeah the longer cycle removed 5-8% moisture. But it did that on the normal blower speed too. So should we leave the equipment alone and move to step two of crawl space seal and whole house dehumidifer? Getting ducts checked too.

I miss the old heat pump with the slider manual tstat. It cycled on and off at long regular intervals...house was cool and dry. I guess I have to sacrifice my house so we can save $1 in power monthly???

I have been trying to think of all the things we did since about 2000 when the house started stinking. One thing was put a new roof on. They cut the slit at the crown larger for breathing and put a new ridgevent on. House kinda felt hotter and smelled after that. Last week we found out it had been leaking slowly and caused some mold to form at the crown of a cathedral ceiling...and on top of that became home to carpenter ants, We have get to get that fixed but I am sure that doesn't help the stink in the house.

[beenthere]

The replacement heat pump. Is it the same size as the old heat pump.

[mkwelbornjr]

Yes. its 2.5 tons. The front unit is much bigger and still has more comfortable cycles.


The replacement heat pump. Is it the same size as the old heat pump.

[mkwelbornjr]

After three days of a slower fan...still not seeing drastic RH reduction. I do think the tech told me he slowed the fan and cut back the cooling load. Perhaps the slow fan should work with a stronger cooling load?

We are next looking int Variable blower and proper tstat or the whole house Dehum. I had also though about moving the unit under the house to the basement room where the front unit is. It would recuqire a few feet of extra duct work, which would give us some new ducts. be easier to service and maintain.

[beenthere]

How did the tech "magically" cut back the cooling load?

What improvement did he make to your house that cut it back?

[mkwelbornjr]

No clue. I am guessing he slowed the flow of freon or whatever the new stuff is called...maybe reduced the pressure. Thats what I was wondering too. Then he said the new unit had coils made of virgin metal so there is no way for it to grow mold or stink. But the ducts did not stink like this prior to the new system. They even stank like burnt mold during the cold of winter.


How did the tech "magically" cut back the cooling load?

What improvement did he make to your house that cut it back?

[beenthere]

In other words, he adjusted the charge.

So its also possible your system is now under charged.

[teddy bear]

[QUOTE=mkwel. So should we leave the equipment alone and move to step two of crawl space seal and whole house dehumidifer? Getting ducts checked too.
.[/QUOTE]
You make a comment about the cracks in the earth in the dry earth in the crawlspace. Crawlspace earth must be covered with plastic and the vents closed. You are cooling with inside temp at 68^F in an effort to control %RH. That is the end of the road for using the a/c to control humidity. The whole house dehu is the only way to control %RH when your cooling load declines. In fact you should not cool below 73^F, because of moisture condensing in the walls and a lack of comfort. I cool to 74^F and remove the rest of the moisture with the dehu. With your duct odor problems, you need fresh air and dry air in the a/c ducts to dry them out. Check out the Ultra-Aire 90 H. That will stop the odors in the ducts while providing the <%RH are any temperature with or without a/c. Regards TB

[mkwelbornjr]

So...beenthere and teddy bear....should we get them to bring the charge back up? leave the fan on low? or bring the fan back to middle?
And we will seal the crawl and install a whole house dehum. Also place a dehum in the crawl too..maybe have All Dry do it? They seem to claim to do all we have discussed on their website...and are in my area. Finally clean the ducts...they have been untouched since 1979.

[beenthere]

You need to have them send a tech out that knows what a proper charge is.
And understands how an A/C really operates/works.

It sounds like they are adjusting charge by looking at pressure. Without checking SC and SH.

Bad thing to do.

[teddy bear]

So...beenthere and teddy bear....should we get them to bring the charge back up? leave the fan on low? or bring the fan back to middle?
And we will seal the crawl and install a whole house dehum. Also place a dehum in the crawl too..maybe have All Dry do it? They seem to claim to do all we have discussed on their website...and are in my area. Finally clean the ducts...they have been untouched since 1979.

A cold enough cooling coil to provide a 20-25^F temp drop of the air passing through the coil is important. High air flow raises the temp of the cooling coil making moisture removal impossible. On the low side of air flow, the coil freezes, not good. During the hottest weather, the a/c should be able to provide <50%RH. A 90 pint whole house dehu will handle the house and the crawlspace. Regards TB

[mkwelbornjr]

OK...so here is my plan. Seal the crawl. Install about a 90pt AprilAire (thats what our tech sells) whole house dehum....and leave the furnace blower as is and set it as it should be set with the one fan speed that works for all the time. On very humid days you can smell that sweet/damp smell creeping up through the floor so definitly the crawl is bringing in the air. We will also get the ducts cleaned.


We have those auto closing plastic crawl vents. Does anyone recommend ones we can install that we can close when we want...and the closure is pretty weather proof?

Also, they must fit inside the standard opening size with no lip on the outside...as the house sits right on the slot where they fit.

[Shophound]

To the OP:

Some of what is contained in the following article might be applicable to your situation:

http://www.baileyeng.com/paston_effect.htm

(thanks to Carnak for the link)

[mchild]

OK...so here is my plan. Seal the crawl. Install about a 90pt AprilAire (thats what our tech sells) whole house dehum....and leave the furnace blower as is and set it as it should be set with the one fan speed that works for all the time. On very humid days you can smell that sweet/damp smell creeping up through the floor so definitly the crawl is bringing in the air. We will also get the ducts cleaned.


We have those auto closing plastic crawl vents. Does anyone recommend ones we can install that we can close when we want...and the closure is pretty weather proof?

Also, they must fit inside the standard opening size with no lip on the outside...as the house sits right on the slot where they fit.

Have you already had the duct work checked for leaks? If, when you turn the blower fan on the humidity rises almost instantly then the moisture has to be coming from either leaky duct work that is drawing moisture in from the crawl space or the condensate catch pan in the air handler is not draining properly. When having the duct work checked make sure where the boot comes through the floor (where the individual supply registers are located) that it is sealed there too. The air passing through the vent grill can draw air from around the boot and that air is moist crawl space air.

[teddy bear]

OK...so here is my plan. Seal the crawl. Install about a 90pt AprilAire (thats what our tech sells) whole house dehum....and leave the furnace blower as is and set it as it should be set with the one fan speed that works for all the time. On very humid days you can smell that sweet/damp smell creeping up through the floor so definitly the crawl is bringing in the air. We will also get the ducts cleaned.


We have those auto closing plastic crawl vents. Does anyone recommend ones we can install that we can close when we want...and the closure is pretty weather proof?

Also, they must fit inside the standard opening size with no lip on the outside...as the house sits right on the slot where they fit.

Get the more dependable Ultra-Aire 90H whole house dehu. We have been making this type of dehu for 20 years. Some of the original models are still operating. Competoitors have only recently stated making cooling devices and have had serious reliablility problems. The high efficiency more reliable UA is a much better value. We will help the tech with the details of install. UAs have a better filter also. Regarding crawlspace vents, close them permentally. They make your space cold in the winter and wet in the summer. I do not mind helping with your problems, but give me a chance for the rewards also. Keep us posted regardless. Regards TB

[mkwelbornjr]

Ultra Aire it will be. I actually gave your tech the brochure you linked me to. Can they be installed with the intake pipe coming out of the return duct right in front of the unit, and the dryer air returning on the other side...without cutting a new return duct into the house? And can a t stat be had that controls the dehumidifier and heat pump at one control?


Get the more dependable Ultra-Aire 90H whole house dehu. We have been making this type of dehu for 20 years. Some of the original models are still operating. Competoitors have only recently stated making cooling devices and have had serious reliablility problems. The high efficiency more reliable UA is a much better value. We will help the tech with the details of install. UAs have a better filter also. Regarding crawlspace vents, close them permentally. They make your space cold in the winter and wet in the summer. I do not mind helping with your problems, but give me a chance for the rewards also. Keep us posted regardless. Regards TB

[mkwelbornjr]

One other thing worth noting. We have some leaky ridge vents on the roof. That research got me wondering. This stinky smell got worse after 2000 when we put a new roof on. The roofer cut the ridge vent slits wider to let more air out. Is it possible the attic could be too vented? The attic is only over the back of the house which sits on the crawl space.

[teddy bear]

Ultra Aire it will be. I actually gave your tech the brochure you linked me to. Can they be installed with the intake pipe coming out of the return duct right in front of the unit, and the dryer air returning on the other side...without cutting a new return duct into the house? And can a t stat be had that controls the dehumidifier and heat pump at one control?
Not good to get the return air from the a/c return. Best to get air from open part of the home. This allows the dehu to operate by getting air from the home and using the a/c supply/return ducts for distribution of the dry throughout the home. Sucking on the a/c return encourages dry air to go back through the air handler to the dehu without circulating through the home. The objective is allow independent operation of both the a/c and wh hs dehu when cooling or drying is needed. I appreciate the opportunity to demonstrate keeping a home dry. Keep us posted on your progress. Regards Ken

[mkwelbornjr]

So if we go with the variable blower option...will that blower work fine with the new split system compressor...it is NOT dual stage...or will we have to replace both parts?

[beenthere]

VS blowers work fine for both single and 2 stage A/Cs.

[Carnak]

To the OP:

Some of what is contained in the following article might be applicable to your situation:

http://www.baileyeng.com/paston_effect.htm

(thanks to Carnak for the link)

That effect is really about infiltration that someone with only a northern frame of reference thinks only happens in the winter.

It takes a minute for my CO2 meter to warm up. Every time so far it is high RH and low CO2 it means there is way too much outside air moving through the building, it then becomes a matter of figuring out what is causing the air movement and a lot of the time it is an unintentional mechanical cause.

One 'classic house' fitting the description in the effect, already had a couple 70 pint per day dehumidifers installed, and I was figuring they had air moving through at the equivalent of 400 CFM. Anyways to keep on with the band-aid approach, they needed three more dehumidifers.

They had a dinner party with 20 guests and indoor CO2 spiked to about about 900.

It turned out that a return chase was built by the general contractor in the attic space of a gallery, sort of like a narrow corridor with outside walls connecting two sections of the home. Whte metal roofing, bubble wrap along the pitch, R19 at ceiling plane, continuous perforated soffit vents. Did not get hot in this gallery attic.

A year or so prior, the AC tech noticed that the main retrun on one system was cooler than what was measured at the unit, so he did hs best to patch up the leaky chase. It was assumed the leak was solved. The attic air was maybe 82F and humid, the owners of this estate are cheap and set up the temperature all the time, space could be 80-82 unless they were actually in this section of the estate so based on measuring return air at grille after the repair and what was entering the unit, you could not notice much of a difference.

Dehumidifers were installed in the bypass mode, drawing return from the AHU returns and supplying the dry air to the AHU supply duct, and wired to bring on AHU fan when the dehu ran.

Was like "putting out fire with gasoline". Constant fan re-evaporated mositure and the root cause of the problem was return duct leakage. Dehu was almost always calling so the AHU fan never shut off. It dried out its coil after every cooling cycle and was drawing in a large amount of fresh air.

The system where the return leak was supposedly repaired was a 4 ton, ECM AHU. I dropped the fan speed down on the dip switches to 1400 CFM, turned on the "Comfort R" ramping etc while I was poking around.

I ended up strapping a dew point probe to the return grille and one in the AHU return plenum.

I let it be for a few days, recorded readings every minute. When you looked at the dewpoints on a p-chart you could tell it was 25% outside air entering the unit, the return chase was still leaking.

So back when it was operating at 1600 CFM, it was pretty much drawing in 400 CFM of outside air, and my CO2 meter said that to me a minute after I showed up.

humidity problems when you are running cooling is usually an infiltration problem. You get the IAQ experts in there and if they see no fresh air intakes on a moldy house they always say "add more fresh air", but the root cause of the problem is too much fresh air is already moving through the home in an uncontrolled manner.

[mkwelbornjr]

Thanks. And will the tstat let you select and set a lower fan speed manually from the tstat control.


VS blowers work fine for both single and 2 stage A/Cs.

[beenthere]

It can be set to lower the blower speed when the humidity gets above set point.
But you can't set speed randomly. As in select a higher speed one moment. And then set it run run faster that night.

Its preset in the blower control programming in the air handler..

[mkwelbornjr]

It seemed the old units with the slider tstat just ran more evenly...on more than off.

[Xavier]

[QUOTE=Carnak;4376602]That effect is really about infiltration that someone with only a northern frame of reference thinks only happens in the winter.

Air Handlers creating a Delta P between inside a building and the outside of a building is not called “Infiltration” by any expert in the North, South, East or West. :anyone:

It is called: Sloppy Workmanship!

However, it is enlightening to finally read how many others understand how important it is to control air exchanges (both mechanical and natural) in homes. The Minnesota Department of Energy has been explaining it for 20 years and I have been explaining/teaching it for more than 30 years.


Please Read BELOW!:angel:

[Carnak]

That effect is really about infiltration that someone with only a northern frame of reference thinks only happens in the winter.

Air Handlers creating a Delta P between inside a building and the outside of a building is not called “Infiltration” by any expert in the North, South, East or West. :anyone:

It is called: Sloppy Workmanship!

However, it is enlightening to finally read how many others understand how important it is to control air exchanges (both mechanical and natural) in homes. The Minnesota Department of Energy has been explaining it for 20 years and I have been explaining/teaching it for more than 30 years.


Please Read BELOW!:angel:

X, I am not going to comment on your intellect again, but you seem to like to pick a fight with me and then cry to the administrator about me when I respond.

The paston effect is out of your frame of reference, it has a lot to do with attics. So perhaps read it over, try and grasp what it says or otherwise "STFU"

The leakage I discussed in the post could very well happen when you line floor joists for a return, and more so when you have a high and low wall return grille in a stud space

[Xavier]

Thanks again for showing everyone on HVAC your lack of professionalism when someone disagrees with your post and explains why it was nugatory.

[ArmedCitySlickr]

mkwelbornjr,

I thought I'd chime in since you are located in the Upstate of SC, as am I. I really feel you need to address the issue of humidity entering your house by blocking it versus just trying to remove it from the air. Your best bet is to start with an encapsulated (sealed) crawlspace. This will be done by sealing the crawl vents and covering the floor, walls, and piers with a 20mil poly liner. All seams are sealed and taped as well as edges sealed to the walls. This will be the first big step to preventing moisture from even entering the house and will make removing what moisture is left a winning battle.

Here are 3 companies in your area that all offer an encapsulation system, get a quote from all 3 (or more) as prices vary greatly given the current economic situation.

All-Dry of the Carolinas
http://www.all-dry.com/contact.php
Steamatic of the Upstate
http://www.steamaticsc.com/
Glenco
http://www.sealcrawlspace.com/

Other suggestions....
1) Seal any gaps in the crawlspace with caulk or expanding foam spray.. around crawl space door, the sill plate @ foundation wall, etc
2) An HVAC supply to the now sealed crawl space
3) A dedicated dehumidifier for the crawlspace such as: http://www.sylvane.com/santa-fe-advance-dehumidifier.html
4) Remove insulation from sub-floor and insulate perimeter walls with an aluminum foil based insulation: http://www.insul.net/prod_astrofoil_all.html

If you're a DIY'er than this company is THE place to shop from...




I fully believe this will cure your high humidity problems. Contact me if you have any questions because I have had this done to my house.

[beenthere]

Armed.

Read site rules before posting again.

This is not a forum for DIY, or suggesting DIY.

[Carnak]

Thanks again for showing everyone on HVAC your lack of professionalism when someone disagrees with your post and explains why it was nugatory.

you never read the link the post was about.

The link had nothing to do with workmanship or anything you commented on, your comments were irrelevant to what I was discussing. The link was about estate sized coastal homes in South Florida I am sure you see lots of them in Michigan along with the issues of hurricane shutters and proximity to salt water, and attic venting- how you get infiltration when there is no northern stack effect occuring.

So you were not disagreeing with me or disputing anything. But what you were doing is you were fixating on me, one more time.

I have no problems trading barbs with the likes of you. But what you do is stir it up and then cry to the administrator about me.

So read the link, discuss it or heed prior advice

[ArmedCitySlickr]

Armed.

Read site rules before posting again.

This is not a forum for DIY, or suggesting DIY.


I did not think the DIY restriction applied to this situation because it was not related to HVAC work.

[beenthere]

While its not HVAC.

After one person see's a link to a DIY site. Then other people start to post links to HVAC related DIY sites.

It snowballs

[mkwelbornjr]

Thanks for the advice. I will followup on the crawl space leads. We will also have to have the ducts checked for mold or whatever can be done as they do stink...even during the winter when the RH was LO and the heat was running. It was like a dry eye burning musty smell....now during the summer it smells like rotten algae soaking in dirty water. All this started after we installed the new unit. Our old unit had gotten rusty due to sweating and a clocked drain line. The air from the ducts smelled like wet metallic...not kidding...and you could smell it in our clean clothes after wearing them around for a few hours away from the house. I am wondering if the old unit polluted the ducts.

I can assure you we will not be doing anything without the help of a professional!

Where in the upstate are you? And is encapsulation a solution even if the soil in the crawl space is damp up next to the foundation wall? I wonder if our recently new sprinkler system could be soaking the ground too much...or perhaps when we re-roofed the roofer cut the ridge vents too big causing suction in the house. Lots of puzzles here.




mkwelbornjr,

I thought I'd chime in since you are located in the Upstate of SC, as am I.

[mkwelbornjr]

Just an update. We are still waiting to start work on duct inspection, crawl space sealing, and dehumidifiers.

But its been raining good for 2 days. House smells really moldy in the back over the crawlspace. Thankfully I see no new mold in the house yet. The air coming out of the ducts smells so bad it make one nauseous. So in the pouring rain I decided to go under the house and look at every inch. The dirt is still dry but maybe slightly damp near the foundation walls...not wet...just not dry. The supply ducts..and the air handler...and the area in front of the airhandler that the supply ducts come out of are all dripping wet. The ducts are wrapped in insulation that has a dull silver backing on the outside. It looks and feels wet. When I touch it water drips. Not sure if this water is only outside due to humidity or in the ducts too. It would explain the odor if in the ducts. The crawl space smells earthy but in no way does it stink or anything. The smell in the ducts in not present in the crawl space. One corner of the crawl had 2 inches of standing water. Directly outside this area is a flat area of grass that is always squishy and water bogged. We put drains in but I just dont think its sloped enough for the drains to pull out much water. Landscapers seem to think water will flow across level thick grass and into drains.


Are we going to have to rip out all the duct work?

[Shophound]

Just an update. We are still waiting to start work on duct inspection, crawl space sealing, and dehumidifiers.

But its been raining good for 2 days. House smells really moldy in the back over the crawlspace. Thankfully I see no new mold in the house yet. The air coming out of the ducts smells so bad it make one nauseous. So in the pouring rain I decided to go under the house and look at every inch. The dirt is still dry but maybe slightly damp near the foundation walls...not wet...just not dry. The supply ducts..and the air handler...and the area in front of the airhandler that the supply ducts come out of are all dripping wet. The ducts are wrapped in insulation that has a dull silver backing on the outside. It looks and feels wet. When I touch it water drips. Not sure if this water is only outside due to humidity or in the ducts too. It would explain the odor if in the ducts. The crawl space smells earthy but in no way does it stink or anything. The smell in the ducts in not present in the crawl space. One corner of the crawl had 2 inches of standing water. Directly outside this area is a flat area of grass that is always squishy and water bogged. We put drains in but I just dont think its sloped enough for the drains to pull out much water. Landscapers seem to think water will flow across level thick grass and into drains.


Are we going to have to rip out all the duct work?

What you now say makes me think the source of odor is within the ductwork and air handler. If the ducts are sweating everywhere, the insulation on them is next to worthless. It is likely the external vapor barrier around the insulation was not sealed well, so moisture has driven into the insulation, compromising its ability to slow heat transfer. If this is happening on your return ductwork, any leakage in the return plenum (and trust me, there's bound to be some leakage there) is pulling crawl space air, which is humid, into the insulation through gaps in the insulation vapor barrier, where the moisture eventually condensed on the cold metal surface of the return plenum. This has continued until the insulation became thoroughly soaked, rendering it useless for slowing heat transfer. It has also become a food source for mold or mildew.

It is also aggravating your a/c performance. Since your duct insulation is worthless, you're losing cooling capacity to the crawl space, so your system runs longer to satisfy the thermostat setting. Since it runs longer, the ducts stay cold longer, so the insulation never can dry out. The insulation keeps getting more and more wet, creating more areas for mold to grow. It's a snowballing effect.

Have your ducts thoroughly inspected, but research carefully for somebody who is expert in this. Unfortunately many HVAC contractors doing residential work have an inherent phobia about ducts. They'll fling 'em everywhere in an attic or basement or crawler, but putting them in so they'll last forever, and finding out what's going on with airflow and moisture problems after the fact...it often eludes them.

[Shophound]

It's also possible (probable) there is mold growing on any insulation inside the air handler and supply plenum. If that insulation is wet then it is also worthless.

[ArmedCitySlickr]

It sounds to me - more and more - that it's a humidity issue in the crawlspace. You most likely will not need to replace the ducts, just the insulation on the ducts. What sounds like is happening is high humidity in the crawl space is causing condensation on the ducts ( think of taking a cold glass of water outside on a humid day). This condensation is then absorbed by the fiberglass insulation and starts a breeding ground for mold to grow, now you have a return duct that is pulling this odor/mold into the ducts through normal leakage and is distributing it throughout the house.

The only way to stop condensation from forming on the outside of duct work is to place them in a conditioned environment, such as a sealed crawlspace. So once again my suggestion is to....

1st seal the crawlspace and prevent/minimize moisture from getting in
2nd dehumidify the crawlspace to remove any excessive moisture in the air, insulation, and wood that has been absorbed for 20+ years.
3rd remove the insulation from around all the duct work and replace it with fresh stuff.
4th duct cleaning may be necessary depending if mold has been sucked into them and began growing.

There is no reason to replace the ducts without first conditioning the environment that the ducts are in, otherwise in just a few days time the insulation around the new ducts will be soaked again.

[mkwelbornjr]

Thanks. I will be working on getting someone up here. The heil book said the air handler needed to be wrapped in insulation too when installed in a crawl space. Of course thats not the case here.

The unit up front, on the part of the house over a garage and rooms...has been off for a while. There are some rooms of the front unit over the crawl as well. The intake duct in the one of 2 rooms over the crawl has that gross smell backing out of it. Same smell in the back of the house that backdrafts out of the intake ducts....and supply ducts.

[mkwelbornjr]

Could I remove a panel on the airhandler and see for myself? Would pics of anything (posted here) be helpful? I am good at taking pics and dont mind doing it.



It's also possible (probable) there is mold growing on any insulation inside the air handler and supply plenum. If that insulation is wet then it is also worthless.

[mkwelbornjr]

ArmedCitySlickr, is there anyway you can contact me via email since you had the crawlspace sealed....it would be nice to talk one on one with something that had that done.

As a side note...the plenum areas of the air handler are exposed sheet metal...the door that is removed to replace the Space Gard air filter is covered in black mold. The metal housing the space gaurd filter slides into is rusted out completely.



It sounds to me - more and more - that it's a humidity issue in the crawlspace. You most likely will not need to replace the ducts, just the insulation on the ducts. What sounds like is happening is high humidity in the crawl space is causing condensation on the ducts ( think of taking a cold glass of water outside on a humid day). This condensation is then absorbed by the fiberglass insulation and starts a breeding ground for mold to grow, now you have a return duct that is pulling this odor/mold into the ducts through normal leakage and is distributing it throughout the house.

The only way to stop condensation from forming on the outside of duct work is to place them in a conditioned environment, such as a sealed crawlspace. So once again my suggestion is to....

1st seal the crawlspace and prevent/minimize moisture from getting in
2nd dehumidify the crawlspace to remove any excessive moisture in the air, insulation, and wood that has been absorbed for 20+ years.
3rd remove the insulation from around all the duct work and replace it with fresh stuff.
4th duct cleaning may be necessary depending if mold has been sucked into them and began growing.

There is no reason to replace the ducts without first conditioning the environment that the ducts are in, otherwise in just a few days time the insulation around the new ducts will be soaked again.

[ArmedCitySlickr]

Im concerned about the mold in the air handler, but again, replacing the ducts and HVAC system may only be fixing the symptom not the underlying problem. It sounds like we really need to find out why there is mold in the system... Is it because of excessive moisture? If so, where is the moisture coming from and how can we stop it? If it's not moisture then what is it?

If you can pick up a humidity meter (hygrometer) from walmart or radio shack and put it in the crawl space and in the house then that would tell us pretty quickly if there is a moisture problem that is feeding the mold....

Leave me an email address and I'll contact you. I was going to send a private message but apparently that option is not available on this message board.

-Alex

[mkwelbornjr]

No email addresses in post, put it in your profile. I would assume the crawl space, since its vented, would have the same RH as outside would have. So 80% or more on a wet day like today. In the house, in the back some rooms are 55% some are 62%...by morning most will reach 67%. We do have a wet area in the yard at the corner of the house. The outside soggy area is 5 feet above crawl space floor which today had 3 inches of water standing under the house in the corner. We had landscapers put drains in, then they sodded but its really soggy there. I think the grass just damns the water up so it can't reach the drains.


Im concerned about the mold in the air handler, but again, replacing the ducts and HVAC system may only be fixing the symptom not the underlying problem. It sounds like we really need to find out why there is mold in the system... Is it because of excessive moisture? If so, where is the moisture coming from and how can we stop it? If it's not moisture then what is it?

If you can pick up a humidity meter (hygrometer) from walmart or radio shack and put it in the crawl space and in the house then that would tell us pretty quickly if there is a moisture problem that is feeding the mold....

Leave me an email address and I'll contact you. I was going to send a private message but apparently that option is not available on this message board.

-Alex

[Carnak]

RH is a confusing term as it changes with temperature

The crawlspace will have the same dew point as ambient air, but the crawl space tends to be cooler than the outdoor air, so the RH in the crawlspace will be higher than the outside air.

http://www.buildingscience.com/documents/insights/bsi-015-top-ten-dumb-things-to-do-in-the-south/

[Shophound]

Could I remove a panel on the airhandler and see for myself? Would pics of anything (posted here) be helpful? I am good at taking pics and dont mind doing it.

Your safety is the most important aspect of my reply to your question. All power to air handler to be shut off if you do this. Pics would be helpful. If you find mold on any surface inside that air handler, it's a no brainer it's not just where you're seeing it.

[mkwelbornjr]

Yes, would definitly shut off power before taking a peak. Another issue I thought of was negative pressure. I honestly don't think our house is too tight. Its cypress clapboard with tons of gaps at the places where pieces come together. Soffets have gaps too. And under the clapboard is the old 70's Rmax styrofoam with a foil facing. I doubt it was sealed at the seams knowing the guys who built the house. But this odor and dampness issue worsened after we glassed in a porch and stole some air supply from the crawl space unit to feed the porch. All returns are in the back rooms. Perhaps causing negative pressure..pulling more than usual the damp air out of the crawl?

[beenthere]

No email addresses in post, put it in your profile. I would assume the crawl space, since its vented, would have the same RH as outside would have.

Put you email address in your profile.

[mkwelbornjr]

Done sorry. Didn't realize the profile had that feature.


Put you email address in your profile.

[mkwelbornjr]

Email has been posted on my profile if anyone would like to email me....especially ArmedCity so we can discuss the crawl space issues.

I am just stumped as to why after 30 yrs of living here since new...the smells are all of a sudden horrific. The air out of the ducts smells...but when the system is off the rooms smell the same way...sour and sharp...like mold. I didnt see mold under the house..maybe a few black spots on the underside of the floor where insulation was missing...but that will be common in a dirt crawlspace.

[teddy bear]

Email has been posted on my profile if anyone would like to email me....especially ArmedCity so we can discuss the crawl space issues.

I am just stumped as to why after 30 yrs of living here since new...the smells are all of a sudden horrific. The air out of the ducts smells...but when the system is off the rooms smell the same way...sour and sharp...like mold. I didnt see mold under the house..maybe a few black spots on the underside of the floor where insulation was missing...but that will be common in a dirt crawlspace.
Standing water in the crawlspace, mold visiable where the insulation is missing, and many other problems make it difficult for us to help you. The last clue, visible mold on the floor is the key. Moisture condenses under insulation and the bottom of the floor. Insultation on a cold floor requires a perfect vapor barrier on the damp side of the insulation. You do not have much of vapor barrier. The floor is cooled and the dew point in the crawl is high. High humidity, near condensation every summer starts the mold growing. Over the years, the mold will grow on the cooled floor surface over the years to the point where it will stink. Over cooling the home aggrevates the proble.
Wait another month and the problem will subside until next year.
Regards TB
Pump the water out/sump pump, cover the earth/water with a heavy plastic, close the vents, and maintain <55%RH throughout to eliminate the odor.

[mkwelbornjr]

Thanks. Well the main issue has been addressed by yall...and we are going to start working on it. If I see small amounts of mold on the floor will we need to rip that wood out? And I am not sure how a moisture barrier on the backside of the insulation would help...as you still have a way moisture can get around the insulation where the joist is. What about fresh insulation then put plastic underneath the joists...essentiall encapsulating the insulation. We have that old paper backed insulation.

The furnace is the main issue. We did slow the blower down. Would there be much more to gain by replacing the blower with a variable speed unit and matching proper t-stat? And we are researching the Ultra Air whole house dehumidifier. We left our Hvac contractors with the info and never heard back from them. And they for some reason refuse to check the duct insulation. They told us to just spray deodorizer into the return ducts. I will take some pics and post in the next couple days of whats under the house. The plenum, where the door is to remove the filter (Space Gaurd) is rusted and covered in black mold.

[mkwelbornjr]

Shouldn't we start outside to stop the water to begin with? Then pump after that step?



Pump the water out/sump pump, cover the earth/water with a heavy plastic, close the vents, and maintain <55%RH throughout to eliminate the odor.

[Shophound]

Thanks. Well the main issue has been addressed by yall...and we are going to start working on it. If I see small amounts of mold on the floor will we need to rip that wood out? And I am not sure how a moisture barrier on the backside of the insulation would help...as you still have a way moisture can get around the insulation where the joist is. What about fresh insulation then put plastic underneath the joists...essentiall encapsulating the insulation. We have that old paper backed insulation.

The furnace is the main issue. We did slow the blower down. Would there be much more to gain by replacing the blower with a variable speed unit and matching proper t-stat? And we are researching the Ultra Air whole house dehumidifier. We left our Hvac contractors with the info and never heard back from them. And they for some reason refuse to check the duct insulation. They told us to just spray deodorizer into the return ducts. I will take some pics and post in the next couple days of whats under the house. The plenum, where the door is to remove the filter (Space Gaurd) is rusted and covered in black mold.

Click below to learn about building science and crawl spaces:

http://www.buildingscience.com/documents/insights/bsi-009-new-light-in-crawlspaces/?topic=/doctypes/building-science-insights


In short, you won't get satisfaction with this problem until you target the source of moisture feeding the mold growth. As to why you haven't had any problem until now, on site forensics would be the best way to determine that. Doing it over the 'net is a hit and miss affair at best.

[mkwelbornjr]

Would be nice to have someone come out...but its hard to separate the legit from the scams that use mold as scare tactics.


Click below to learn about building science and crawl spaces:
As to why you haven't had any problem until now, on site forensics would be the best way to determine that. Doing it over the 'net is a hit and miss affair at best.

[teddy bear]

Thanks. Well the main issue has been addressed by yall...and we are going to start working on it. If I see small amounts of mold on the floor will we need to rip that wood out? And I am not sure how a moisture barrier on the backside of the insulation would help...as you still have a way moisture can get around the insulation where the joist is. What about fresh insulation then put plastic underneath the joists...essentiall encapsulating the insulation. We have that old paper backed insulation.

The furnace is the main issue. We did slow the blower down. Would there be much more to gain by replacing the blower with a variable speed unit and matching proper t-stat? And we are researching the Ultra Air whole house dehumidifier. We left our Hvac contractors with the info and never heard back from them. And they for some reason refuse to check the duct insulation. They told us to just spray deodorizer into the return ducts. I will take some pics and post in the next couple days of whats under the house. The plenum, where the door is to remove the filter (Space Gaurd) is rusted and covered in black mold.

If the blower is slow enough to provide a 20^F temp drop of the air being cooled, not necessary to replace the blower. There are other ways to slow air flow to increase dehumdifing of the air during cooling. Check with your a/c contractor.
Not necessary to remove the wood. When you reduce the dew point of the air in the crawl, mold growth will stop and become dormant. In most cases, odor ceases. Maintaining <55%RH in the crawlspace should take care of the issues. Misinformation is usually a matter of a lack of knowledge.
Regards TB

[Shophound]

Misinformation is usually a matter of a lack of knowledge.
Regards TB

Well said.

[mkwelbornjr]

Starting to think we have negative pressure in the house which helps fuel the mold/stink problem causing humid air to be pulled in. We have a clapboard house (cypress) built in 1979, I wouldn't think its that tightly built. But something we did within the recent 5 yrs created a negative pressure. I will get under the house Thurs and start taking some pics to post of the heat pump etc.

[Shophound]

Starting to think we have negative pressure in the house which helps fuel the mold/stink problem causing humid air to be pulled in. We have a clapboard house (cypress) built in 1979, I wouldn't think its that tightly built. But something we did within the recent 5 yrs created a negative pressure. I will get under the house Thurs and start taking some pics to post of the heat pump etc.

May I ask what has caused you to suspect your home may be operating in a negative pressure? The main causes of a house interior being of a lower pressure in respect to outdoors are HVAC duct leakage, indoor exhaust fan usage, winter building stack effect, combustion appliance and/or fireplace usage. In summertime the building stack effect is less pronounced; with an overheated attic not sealed well to the house at the ceiling plane it's possible to have "reverse stack effect" whereby superheated attic air, expanding in all directions, forces its way into the house through unsealed openings in the ceiling plane.

So, what are you thinking has occurred over the past five years to put your home interior into a negative state? I'm pondering over this, in that your personal investigations to date seem to limit the source of foul odor to the HVAC ducts. Interior negative pressure can lead to moist air passing through wall cavities and possibly condensing on the interior side of the wall cavity, creating favorable conditions for mold growth. This can possibly occur if the house interior is kept very cool (which often is done in humid climates in attempts to dehumidify the space), so that the drywall facing the insulation in the wall cavities is at or below the dew point of air leaking into the structure from outdoors. There is greater risk for mold growth within wall cavities if the interior walls are covered in low perm materials, such as vinyl wallpaper, which do not allow the cavity to dry to the interior of the home.

Regardless of all that academic talk, I keep coming back to your ducts, and think your focus should remain there until there is no sane reason to keep it there.

[mkwelbornjr]

Well...we did glass in a porch and send some supply from the back unit to the porch..3 ducts worth...but there is no return on the porch. Perhaps that is creating a mini negative pressure in the house in certain areas? When we open the porch door it blows into the rest of the house. Could simply be the return in the nearby kitchen pulling the air too. Could be leakage in the ducts too. I recall in the past a temporary mildew smell from the ducts but it went away. This odor now is gross moldy..worse than mildew..and started where you would just smell it around the house at night mainly. And in clean clothes after you wear them around outside...same smell. Then it got worse to where the air out of the ducts smelled slightly bad...to now even worse. Even during dry heating season the air smelled like burnt oil/cigarette smoke...made our eyes water it was so harsh. No smoke though, thats just the best way to describe it. Our installers are worthless...we are looking for others.

I am sitting here now as I type...started to pour...almost immediately I smeel and feel a damp wet smelling draft move across. And I am in a room over the crawl space...but ducts come from the front unit that doesnt stink. It smells in here too like it does in the back areas. It seems to get worse in here when the back unit turns on. Making me think neg pressure. Vent fans not really an issue as we have to rebuild all those. The house builders didnt put pipes on the bathroom vent fans and covered them with insulation.

[Shophound]

If you are trying to cool a glassed in porch with no return, and that porch is not airtight, you are definitely pulling your house into a negative pressure in respect to outdoors.

It could he worse than just a mini negative pressure. You have three ducts going out there with no return. Next time your back system runs, leave the door to the glassed in patio closed. Go to a different door that leads outside, like the front door, and crack it open just a hair (be sure there's no wind outside when you do this, or if you have a door leading to a garage, that's even better). If you feel air entering your house through this door, barely cracked open, you're likely negative. If you hold up some facial tissue and it trails into the house, that's even better evidence.

[mkwelbornjr]

Yes...I can confirm their is major inward airflow when opening a door. That could be the changed that occured in 2001 that made the smell worse. Yes the crawl is too damp, but perhaps the negative pressure from the new porch supplies made it worse. But it could be due to a differential within the house...not leaks in the porch.

[Shophound]

Yes...I can confirm their is major inward airflow when opening a door. That could be the changed that occured in 2001 that made the smell worse. Yes the crawl is too damp, but perhaps the negative pressure from the new porch supplies made it worse. But it could be due to a differential within the house...not leaks in the porch.

What I'm suggesting is that when you blow air into the porch with the porch isolated from the house, you are blowing air through the porch enclosure itself to the outdoors, causing the house proper to go negative.

I suspect, but cannot confirm without being onsite, that your house going negative is an aggravating factor to your foul odor problem. You may be pulling air through wall cavities from the crawl space and outdoors to make up air being lost through the leaking porch. Moisture in this air may be condensing inside building cavities when it strikes the cool drywall that faces the cavities. There could be other similar scenarios going on.

I would make provision to the enclosed porch for a dedicated return air source, even if it's as simple as cutting a hole in the wall between the porch and house (sealing the hole frame so it also does not leak) and placing a decorative grill over it so the porch and the house can be equal in pressure when the back a/c system runs. It may not solve your odor problem, but it needs to be done regardless.

[mkwelbornjr]

Here are some crawlspace and heatpump photos I took today. IMO the air handler does not look level...drip line end looks high. Drip line runs across crawl to drain in that pipe shown where there is standing water as seen. In some areas the builder just left off insulation. The gully in the crawl is very dry.

http://s454.photobucket.com/albums/qq263/mkwelbornjr/House%20Pics/

[Shophound]

The PVC pipe with the smaller section tapped into the larger section...is that sewer or sump pump water? Also looks like pipe is cracked by fitting and evidence of whatever the pipe carries has been leaking out. Whatever this pipe carries, if it's leaking it should be fixed.

Bare sections of dirt look wet near foundation walls. Is it? Also saw sections under poly that look wet.

Joist bays missing insulation...not helping your heating/cooling bills at all.

Fiberglass insulation in joist bays with no kraft paper facing out...what's to stop convective air currents from setting up through the fiberglass?

Ductwork with old gray vapor barrier external liner...torn in spots, insulation showing at seams...this is a setup for condensation to occur on the bare metal duct material underneath the insulating jacket. Only way to prevent ducts from sweating with insulation is to seal the insulation so air cannot penetrate it...either going into the insulation (via convection or pressure difference) or going out via the same means.

Duct elbows, joints, and plenum seams not sealed with mastic. From an armchair's perspective this duct system needs help big time in the insulation and sealing aspects. I also would not abide non insulated joist bays in a ventilated crawl space. Just asking for trouble.

[Shophound]

One more thing...that condensate drain piping trap by the air handler; I hate those "running traps". They're worthless. You need a deeper trap on there with a tee and standpipe on the downstream side to allow the downstream piping to drain properly. Water staining on cinder block supports underneath AHU indicate this drain pan has overflowed in the past...possibly because this is a heat pump and the trap is sucking air backward into the blower. Could also be the source of your foul smell if this drain line is tapped into sewer or gray water drainage.

I also don't like seeing the air handler on cinder blocks! How can you assure it is level that way? Get it up on unistrut, ideally, and level according to manufacturer's recommendation.

[mkwelbornjr]

The pipe that is leaking is the condensate drain from the Heat Pump...draining into some odd pipe. I assume all that water on the dirt below the pipe is leaking condensate...as it is always wet there. And no clue where that larger white pipe goes..its has holes in it...as if some type of french drain. I am going to seal the crawl...replace any floor insulation needed...re-wrap ducts and check for poor connections. Hopefully that will give me a positive start here.

Yeah, by looks the unit does NOT look level to me. The drain did leak on the previous unit...hence the stain on the block. If I had it to do all over again, we would put the unit in the basement room and runs some more ducts...or put in one of those all-in-one outside units.

The dirt is dampnear that one side of the foundation...I took pics of the outside area too..its a small grass strip below a bank. We installed sprinklers...I think those keep it soggy outside. During a hard rain I went under..there was 3 inches of water in the corner near the end of the pics.

What do you think of the air filter housing and unit? Can that be improved?

[Shophound]

The pipe that is leaking is the condensate drain from the Heat Pump...draining into some odd pipe. I assume all that water on the dirt below the pipe is leaking condensate...as it is always wet there. And no clue where that larger white pipe goes..its has holes in it...as if some type of french drain. I am going to seal the crawl...replace any floor insulation needed...re-wrap ducts and check for poor connections. Hopefully that will give me a positive start here.

Yeah, by looks the unit does NOT look level to me. The drain did leak on the previous unit...hence the stain on the block. If I had it to do all over again, we would put the unit in the basement room and runs some more ducts...or put in one of those all-in-one outside units.

The dirt is dampnear that one side of the foundation...I took pics of the outside area too..its a small grass strip below a bank. We installed sprinklers...I think those keep it soggy outside. During a hard rain I went under..there was 3 inches of water in the corner near the end of the pics.

What do you think of the air filter housing and unit? Can that be improved?

First thing I'd do is get the condensate drain rerouted away from that PVC pipe. It looks like whoever installed it there just drilled a hole in the larger pipe and tried to thread a fitting into it for inserting the 3/4" PVC pipe. The larger pipe cracked and it now leaks. The condensate should drain elsewhere. The large pipe might be a french drain, or it might be something else.

The running trap on the air handler may not be holding its prime when the air handler runs. When this happens, it draws whatever water flows into it back into the air handler. The drain pan below the cooling coil can't drain properly. Without sufficient priming water the trap will pull air through the entire length of the drain piping and into the air handler. From where I sit it's pulling air out of the larger PVC pipe with the crack in it, right next to wet, smelly soil. AND if it's a french drain, somewhere beyond the pipe you see the pipe wall is perforated, allowing whatever water is in the pipe to leach into the soil. Another source for odor.

First thing I'd tackle is the trap and the drain reroute. The hole in the large PVC pipe should be repaired and sealed after the reroute. See if that reduces your odor problem. This is low hanging fruit that might relieve you of the immediate problems of odor and humidity. From there you can tackle the larger issues of moisture mitigation in the crawl space, and insulation of the joist bays.

[teddy bear]

This attached data shows the effect of infiltration of outside damp air into a home during the cooler "no cooling load conditions. As the weather cools, I tried not operating the dehumidifier part of my ventilating dehumidifier while providing 60 cfm of fresh air into my home. It appears that when the outdoor dew point goes above 50^F, the home need a dehumidifier to keep the basement/crawlspace <50%RH. The %RH rose to +60%RH, so I activated the dehumidifier. I will try the same thing next week. Short term, dehumidification is require to keep the basement dry while using the needed fresh to purge indoor pollutants. House is good with minimal 60 cfm fresh air.
Regards TB