HRV System

[kpt_krunch]

Alright - I met with my h-vac contractor today. I'll be getting the Infinity MVP120 for a 2808 + Basement sq.foot home. Four zones with Infinity Zone control, flow-through humidifier, and an HRV System.

I guess there are two types of HRV's from Carrier, one is an electonric one with two fans, and one is a passive one. The Electronic one will run about $3500.00 installed (this is Cdn money) and the Passive one will be $650.00.

He is recommending the passive one, which will draw the cool air in, and when the furnace is on, the cool incoming air will be heated by the outgoing air. If any of you H-VAC contractors were building a home today, and if you were going with the Infinity system - is this a worthwhile upgrade? The other option is to do what I did in my current home, and that was to have the Hoyme Dampers installed. Any advice on this would be appreciated. As an FYI, I am leaning towards the Passive HRV, but do not know enough about it to make an educated decision.

Thanks!!!!

[Carnak]

The passive one sounds like carrier is relabelling a hoyme air exchanger. There will not be much duct work with the passive system. A furnace supply to the unit and return duct connection to the unit and two pipes outside for exhaust and intake.

It will most likely meet code, but I would not install one in my own home.

I would get an HRV with fans, this must be what you are calling the 'electronic one'. I would also make sure that this HRV had decent controls, with an intermittent mode function.

The 'electronic one' you mention has a higher price due in part, to the unit being more expensive but also due to there is most likely a lot of duct work involved. It should include exhaust intakes from each bathroom, the kitchen and possibly the laundry room. It is grabbing air from the areas of highest humidity which you will need to get rid of to avoid window condensation.

These exhaust intakes are ducted to the unit, there are the two ducts outside for intake/exhaust and then there is the tempered fresh air connection most likely to the return air of the furnace.

The quoted price you received sounds like it may have included fresh air supplies directly to areas of the home instead of just supplying fresh air to the return air duct of the furnace.

The first winter after construction, that HRV is going to run steady to dry out all the moisture of construction. By the second winter if you ran it all the time it will over dry your house.

You can control them intermittently with a dehumidistat, they will be off until the indoor humidity rises above a setpoint. Once the humidity starts to rise, the unit will turn on and run until the humidity level drops.

If you have decent windows and depending on where excatly you are in Canada, you should be able to maintain 35% Relative Humidity in the deep of winter.

When it is less cold outside you could maintain 40 to 50% RH without window condensation. Perhaps the 'electronic one' you have been quoted has controls that can determine what the humidity set point is, else you will have to manually trun the humidity setting up and down, but 35% is a good place to start when it gets below freezing outside.

Look out for windows that short circuit heat out around their frames, you want something with a thermal breaks to help avoid U-shaped patterns of condensation.

The Passive one would most likely over ventilate your home, to the point you will end up installing a humidifier. You put in a device to take out humidity then add a device to put something back in.

There is a lot of money in that 'electronic HRV' quote, so it should include a lot of ductwork, like several fresh air supplies to different areas of the house and some bells and whistles on the controls.

Manufactures like Flair, vanEE, and Lifebreathe make good stuff.

Maybe get a couple more quotes before everyone is too busy up there.

Is your house 2808 sq ft PLUS a 2808 sq ft basement?

[Jultzya]

I think I'll just let you re-read Carnak's post.


Originally posted by Carnak
The passive one sounds like carrier is relabelling a hoyme air exchanger. There will not be much duct work with the passive system. A furnace supply to the unit and return duct connection to the unit and two pipes outside for exhaust and intake.

It will most likely meet code, but I would not install one in my own home.

I would get an HRV with fans, this must be what you are calling the 'electronic one'. I would also make sure that this HRV had decent controls, with an intermittent mode function.

The 'electronic one' you mention has a higher price due in part, to the unit being more expensive but also due to there is most likely a lot of duct work involved. It should include exhaust intakes from each bathroom, the kitchen and possibly the laundry room. It is grabbing air from the areas of highest humidity which you will need to get rid of to avoid window condensation.

These exhaust intakes are ducted to the unit, there are the two ducts outside for intake/exhaust and then there is the tempered fresh air connection most likely to the return air of the furnace.

The quoted price you received sounds like it may have included fresh air supplies directly to areas of the home instead of just supplying fresh air to the return air duct of the furnace.

The first winter after construction, that HRV is going to run steady to dry out all the moisture of construction. By the second winter if you ran it all the time it will over dry your house.

You can control them intermittently with a dehumidistat, they will be off until the indoor humidity rises above a setpoint. Once the humidity starts to rise, the unit will turn on and run until the humidity level drops.

If you have decent windows and depending on where excatly you are in Canada, you should be able to maintain 35% Relative Humidity in the deep of winter.

When it is less cold outside you could maintain 40 to 50% RH without window condensation. Perhaps the 'electronic one' you have been quoted has controls that can determine what the humidity set point is, else you will have to manually trun the humidity setting up and down, but 35% is a good place to start when it gets below freezing outside.

Look out for windows that short circuit heat out around their frames, you want something with a thermal breaks to help avoid U-shaped patterns of condensation.

The Passive one would most likely over ventilate your home, to the point you will end up installing a humidifier. You put in a device to take out humidity then add a device to put something back in.

There is a lot of money in that 'electronic HRV' quote, so it should include a lot of ductwork, like several fresh air supplies to different areas of the house and some bells and whistles on the controls.

Manufactures like Flair, vanEE, and Lifebreathe make good stuff.

Maybe get a couple more quotes before everyone is too busy up there.

Is your house 2808 sq ft PLUS a 2808 sq ft basement?

Cause he did an awesome job at explaining the differences! ;)

[Carnak]

Ask the contractor how much heat gets recovered with the Passive one.

Looks like energy prices are rising these days.

Consider it is -25C outside, the 'electronic HRV' recovers 70% of the heat, and you keep the house at 21C.

the temperature difference is 21-(-25)= 46C

If the electronic one recovers 70% or 0.7 x 46 = 32.2C meaning the cold air gets heated by 32.2C, so it would come into the house at -25+32.2= 7.2C

The furnace would have to add 21-7.2C = 13.8C to this air. You are paying for this 13.8C as energy costs.

With the passive one, the furnace could blow out 55C air. You pay to heat this air by 55-21= 34C. And you are blowing this heated air outside but you are putting it through a heat exchanger first.

here is a quote from the Hoyme Site

"As a result, heat transfer proves to be very high as shown in test reports. e.q. Outside temperature of -30 C (-22F) enters the return plenum at +14 C (+57 F). This incoming air is preheated solely by the heat transfer of exhausting air and therefore receiving warm fresh air at minimum cost."

http://www.hoyme.com/airx.html

Hoyme says when it is minus 30C the incoming fresh air will be 14C, the furnace would still have to heat this up by another 7C on top the 34C extra heat it put in. At -25C the incoming air would be a little warmer than 14C but still the furnace would have to add more heat to it.

With the passive system it looks like you are paying to heat air by more than 34C to ventilate and with the 'electronic one' you are only paying to heat ventilation air by 13.8.

So from a heat energy stand point, you are using about 2.5 times the natural gas to heat the air with the passive system compared to the 'electronic one'.

The passive system would add minimal to your electric bill, just some extra little work by the furnace fan.

The electronic one would use a couple fan motors drawing some power maybe a total of 2 Amps at 120 volts.

But you can operate the 'electronic HRV' intermittently, only when it gets too humid, and the passive one would be exchanging air each and every time the furnace runs.

The passive one does not look too thermally efficient. If that MVP is a condensing furnace, 90% efficient, it would probably be more cost effective to have the hoyme intake on the return interlocked with an exhaust fan rather than use that passive system.

If you want to save on installed costs plus get more energy efficiency, get the 'electronic HRV' and pass on the heating zone controls.



[Edited by Carnak on 09-16-2005 at 03:05 AM]

[Carnak]

Thanks jutz!

[seadragon]

Wow! I guess I should come out of my undersea cave a bit more often. I've never heard of these passive HRVs.

All I can add is that we have a Van-EE Gold 1001 ERV and it is great! It made a huge difference in our house, no more consensation. This model is switchable between HRV and ERV. I bought it as an HRV, but have since switched out the core to ERV. This will not dry the house out as much in the winter and allows me to run the unit all year long and through the cooling season.

kpt, where are you located? If you have a longer cooling season, you may wish to get an ERV. I can elaborate if you wish, but the ERV seems to be a better balance of humidity control for both summer and winter.

[ruud-man]

I was very pleased to read your HRV/ERV explanation, specially the dedicated duct system. Many of our local contractors get real lazy and tie the HRV/ERV into the furance supply and return.

They just can't grasp the concept that we don't put return grilles in the kitchen and baths, exactly where the ERV intakes should be.

Nice job...

[Carnak]

Thanks ruud

A house with baseboard heat should have some dedicated fresh air supplies to the bedrooms and living areas.

With a furnace and fresh air from the HRV to the furnace return, I think you get a decent distribution of air.

For new construction you do want the exhaust intakes ducted around.

As a retrofit, to solve a humidity problem, you can draw air from the return duct and supply the air back downstream on the return, closer to the furnace. Easy retrofit in an open basement.

My point was there will be a lot more duct work with an HRV compared to a passive ventilator similar to the one Hoyme sells.

[Edited by Carnak on 09-16-2005 at 03:29 PM]

[teddy bear]

Originally posted by kpt_krunch
Alright - I met with my h-vac contractor today. I'll be getting the Infinity MVP120 for a 2808 + Basement sq.foot home. Four zones with Infinity Zone control, flow-through humidifier, and an HRV System.

I guess there are two types of HRV's from Carrier, one is an electonric one with two fans, and one is a passive one. The Electronic one will run about $3500.00 installed (this is Cdn money) and the Passive one will be $650.00.


An HRV saves a max of $100-$150 worth of heating/cooling a year. Interest/depreciation/operating cost/maintaince per year is $400-$500 a year. Yet you do not have make-up for clothes drier, kitchen hood, or other exhaust devices. Also operating a HRV for bath exhaust is inadequate to clear mirrows after a shower. I sell them but rarely. Usually for electric heated homes at +8000 degree days and high occupancy. I would suggest make-up on the air handler as an option.
Regarding positive pressure in a cold climate and condensation in insulation, consider this. During very cold weather, 50 cfm of warm air will exfiltrate out through the top of a tight home. Also 50 cfm of outside air infiltrates into the bottom. This almost enough fresh air to provide humidity control and indoor air quality. 75 cfm would be adequate and is required to purge indoor pollutants all year regardless of outdoor temperature. A 75 cfm air make-up air system impacts the exfiltration by increasing it to 100 cfm during cold weather and decreasing the infiltration to 25 cfm. This is a 25 cfm increase of cold air needing tobe heated. Operating an HRV does not change the 75 cfm exfiltration/infiltration which must be heated. The point is that HRVs over ventilate a home, do not stop moisture air from exfiltrating and do not save much evergy. U of CA Berkely Labs have researched this. Fresh air ventilation is a must, make-up usually prefered for all the exhaust devices in a home. In green grass climate, consider the need for moisture removal during the summer during low/no cooling load. Careful you may spend 10-15 k and still end up with a wet house during a wet cool summer. TB

[dunburn]

Interesting... this is similar to one of the questions I have - and it might be very applicable in this case (I am in Canada as well). I am interested in the pros and cons of "electronic" versus "passive" systems.

Would not a passive system with humidifer (which is one of the components planned here) combined with an outdoor temperature sensor work? This might help decrease humidity based on the outside temperature... and when combined with a passive HRV (i.e. return ducts only versus dedicated system), would it not balance out? For instance, the running of the HRV would naturally decrease humidity while the humidistat on the humidifier would add humidity -- thereby creating the desired balance?

And, if this is added to a programmable thermostat that drops the temperature at night, would this not automatically decrease the likelihood of condensation at night (when condensation most occurs) because there would not be a call for humidity except when in a heating cycle, and the HRV would decrease humidity naturally when it exchanges the air?

Query: is this for an older home, or a new one? Older homes, like what I have, it is hard (not impossible) to install dedicated HRV systems that connect to the bathroom, kitchen, and laundry fans.

WOW -- the amount of extra energy required to heat that outside (fresh) air seems extensive. That said, I guess it is a matter of trade-offs...?

[Carnak]

Originally posted by teddy bear

Originally posted by kpt_krunch
Alright - I met with my h-vac contractor today. I'll be getting the Infinity MVP120 for a 2808 + Basement sq.foot home. Four zones with Infinity Zone control, flow-through humidifier, and an HRV System.

I guess there are two types of HRV's from Carrier, one is an electonric one with two fans, and one is a passive one. The Electronic one will run about $3500.00 installed (this is Cdn money) and the Passive one will be $650.00.


An HRV saves a max of $100-$150 worth of heating/cooling a year. Interest/depreciation/operating cost/maintaince per year is $400-$500 a year. Yet you do not have make-up for clothes drier, kitchen hood, or other exhaust devices. Also operating a HRV for bath exhaust is inadequate to clear mirrows after a shower. I sell them but rarely. Usually for electric heated homes at +8000 degree days and high occupancy. I would suggest make-up on the air handler as an option.
Regarding positive pressure in a cold climate and condensation in insulation, consider this. During very cold weather, 50 cfm of warm air will exfiltrate out through the top of a tight home. Also 50 cfm of outside air infiltrates into the bottom. This almost enough fresh air to provide humidity control and indoor air quality. 75 cfm would be adequate and is required to purge indoor pollutants all year regardless of outdoor temperature. A 75 cfm air make-up air system impacts the exfiltration by increasing it to 100 cfm during cold weather and decreasing the infiltration to 25 cfm. This is a 25 cfm increase of cold air needing tobe heated. Operating an HRV does not change the 75 cfm exfiltration/infiltration which must be heated. The point is that HRVs over ventilate a home, do not stop moisture air from exfiltrating and do not save much evergy. U of CA Berkely Labs have researched this. Fresh air ventilation is a must, make-up usually prefered for all the exhaust devices in a home. In green grass climate, consider the need for moisture removal during the summer during low/no cooling load. Careful you may spend 10-15 k and still end up with a wet house during a wet cool summer. TB

I would imagine this to be quite a tight home teddy, given the codes in Canada and condensation is a winter time problem. Will range some where from 0.07 to maybe 0.3 natural air changes per hour. This house will be anywhere from 35,000 to 50,500 cubic feet in volume, and without mechanical ventilation those windows are going to condensate like crazy.

The code required mech ventilation rate required in Canada will require systems be installed that will handle somewhere in the range of 175 CFM to 250 CFM in my opinion. It depends on how big the basement is and how high the ceilings are.

It will run at that rate 24/7 the first winter drying out that house. By the second winter it will over ventilate the home and make it too dry if it runs constantly. It would probably run 50% of the time, in intermittent mode, to control humidity.

It would make a big difference where exactly this poster is, but in the colder part of Canada, heating up 175 to 250 CFM of frigid air without heat recovery can add SIGNIFICANT money to the heating bill, especially if the air neeeds to be heated by 90 plus degrees F.

So with today's rising energy prices maybe the HRV deserves a little more respect than the disdain you seem to show it. They save more money than a dehumidifier Nazi realizes :)

You are going to have to rework all your engery cost one liners as costs are sky-rocketting.

Southern Ontario may be 8000 degree days or a little less, Northern Ontario and a lot of western Canada is 10,000 to 12,000 degree days.

The codes in Canada will require equipment with a higher air exchange rate than what seems to be used south of the border as well.

The vapour barriers will stop that moisture exfiltrating.

Bathroom exhaust fans, in addition tot he HRV intakes, for quick odour removal are a good idea.

Will not be an air handler in the Great White North, they call them furnaces up there.

Slight intermittent negatives are not a problem as long as combustion air is properly addressed. Slight negative from intermittent exhausts, in cold climate is not the end of the world.

Big exhaust appliances like Jenn Airs or Italian Canopy hoods are another story all together.

Some jurisdictions in Canada will mandate that if you have a gas burning appliance in your home that uses a B-vent chimney, then you have to use heat recovery ventilation.

A big reason for this rule is they do not want a lot of frigid air getting sucked into the return and mixing the return down too cold as it turns an 80% efficient furnace into a condensing furnace, -the HX has no condensate drain and cannot stand up to acid.

More to HRVs than what energy cost a few years ago in the US. Canadians have been paying more for energy all along, and it looks like the cost is going up again.

Berkley labs need to open a branch up in Saskatchewan.

[Edited by Carnak on 09-16-2005 at 05:07 PM]

[Carnak]

Originally posted by dunburn
Interesting... this is similar to one of the questions I have - and it might be very applicable in this case (I am in Canada as well). I am interested in the pros and cons of "electronic" versus "passive" systems.

Would not a passive system with humidifer (which is one of the components planned here) combined with an outdoor temperature sensor work? This might help decrease humidity based on the outside temperature... and when combined with a passive HRV (i.e. return ducts only versus dedicated system), would it not balance out? For instance, the running of the HRV would naturally decrease humidity while the humidistat on the humidifier would add humidity -- thereby creating the desired balance?

And, if this is added to a programmable thermostat that drops the temperature at night, would this not automatically decrease the likelihood of condensation at night (when condensation most occurs) because there would not be a call for humidity except when in a heating cycle, and the HRV would decrease humidity naturally when it exchanges the air?

Query: is this for an older home, or a new one? Older homes, like what I have, it is hard (not impossible) to install dedicated HRV systems that connect to the bathroom, kitchen, and laundry fans.

WOW -- the amount of extra energy required to heat that outside (fresh) air seems extensive. That said, I guess it is a matter of trade-offs...?



If you are running a humidifier in your home right now, you will not need an HRV.

[kpt_krunch]

Carnack - thanks very much for taking the time to explain it so thoroughly. My apologies for not providing all the info, but you sure did cover all the bases.

I guess I see this device as a filter of sorts as the air comes in, and the plus is that the exhausting warm air from the furnace (which is vented out anyway) will warm up the incoming filtered air and thus allowing my furnace to not work as hard to heat up the air.

I realize it is very hard to explain this when you can't see the home design. Lets start with where I am - the dryest area in Canada - Edmonton, Alberta (well, east of Calgary is the driest I guess, but all of Alberta on a whole is very very dry in the winter). Our winters are not as severe as they are east of us in the prairies (Saskatchewan and Manitoba) but they're certainly not pleasent either.

I will have about 800 sq feet of hardwood on the main floor. We could have gone a two furnace route, but I may want to add A/C for the summer (all 2 and 1/2 months of if it :)) and with one furnace and the home zoned I thought would be the better way to go. I was all set to go with what I have currently - which is hoyme dampers electronically controlled on my combustion air and fresh air intakes (I have two furnaces - both Infinity, one high, one mid in my current home) so they only open when the furnace calls for heat. Since my new home is a much tighter construction, the need for a constant fresh air supply is greater. I plan on letting the furnace run all the time to circulate the air.

I will also have a vented gas fire place on the main level, 3 baths with fans (one super duty one in the 1/2 bath on the main floor, and I upgraded the two fans in the full baths upstairs to a quieter, more efficient model but I did not note the CFM's, only remember being told that they were a lot more efficient and clearing out a room of odour much quicker). The hood exhaust over the stove will be 170 cfms.

My windows (I face NNW) in the front of the home will be a triple pane casement window with two low-E coatings. The rear of the house (which contains the most windows) will be a double pane casement with sunstop and Low-E.

The basement is about 1000 sq. feet. I plan on developing the basement in the future. My zones will be basement, Main floor, Bonus room (over the garage with a vaulted 16 foot ceiling, floor will be over garage, gabled roof will run about an R-25 insulation) and the rest of the second floor (Laundry room, Ensquite/Master bedroom, two other bedroom and bathroom + hallway) with 8 foot ceilings and the insulation in the roof will be R-40. The walls are all R-20. The basment and main floor will have 9 foot ceilings.

I need the humidifier for the home. Even without the hardwood, my 3 year old son and wife both get some nasty nose bleeds in the winter. After upgrading my current home for last winter, and installing a humidifier, the instance of nose bleeds went down. My new triple pane windows I have installed on my old/current home hardly showed any condensation. I have a large bay window, plus sliders in the basement, that weren't upgraded. I had to use a blow dryer and a steel spatula to get the ICE off those windows (tells you how air tight and insulated my current home is - isn't that sad). My fault though - my humidifier is a manual adjustment and I had forgotten to change the setting during a particular wicked cold snap.

So, for my new home, I want to obviously have a solid 40% humidity in the home, even during particularly cold days, without having any moisture buildup. So I upgraded the windows all around (even the ones in the doors)and though I would look into the HRV's.

Your comments are very informative - a bit confusing for a layman like me, and I will be re-reading them a few times, but based on what you said, and what my contractor was telling me (oh - no shopping, this is the company my builder uses and I can't use anyone else) I am starting to see what it all entails. My contractor was also mentioning to me the bathroom fans going back down to the electronic HRV as you did, and that certainly is part of the cost. The contractor seemed to think with our climate, venting the bathroom / range hood air directly outside would be best, and using the 'passive' HRV with the exhaust of the expelled warm air of the furnace to warm up the incoming air would be best.

Carmak, now that you have more information, would you still go with the 'electronic' one and have all the expelled air from the home go through it, dehumidify, warm the incoming fresh air, then go through the furnace and into the home, or just go with the passive one?

I just want to make sure I do what's best for my family to remain comfortable in the home, the wood to not dry out, and of course to use a little energy as possible. I only have one shot at this :)

Thanks for your input!!!!!

[Carnak]

Originally posted by kpt_krunch
Carnack - thanks very much for taking the time to explain it so thoroughly. My apologies for not providing all the info, but you sure did cover all the bases.

I guess I see this device as a filter of sorts as the air comes in, and the plus is that the exhausting warm air from the furnace (which is vented out anyway) will warm up the incoming filtered air and thus allowing my furnace to not work as hard to heat up the air.

I realize it is very hard to explain this when you can't see the home design. Lets start with where I am - the dryest area in Canada - Edmonton, Alberta (well, east of Calgary is the driest I guess, but all of Alberta on a whole is very very dry in the winter). Our winters are not as severe as they are east of us in the prairies (Saskatchewan and Manitoba) but they're certainly not pleasent either.

I will have about 800 sq feet of hardwood on the main floor. We could have gone a two furnace route, but I may want to add A/C for the summer (all 2 and 1/2 months of if it :)) and with one furnace and the home zoned I thought would be the better way to go. I was all set to go with what I have currently - which is hoyme dampers electronically controlled on my combustion air and fresh air intakes (I have two furnaces - both Infinity, one high, one mid in my current home) so they only open when the furnace calls for heat. Since my new home is a much tighter construction, the need for a constant fresh air supply is greater. I plan on letting the furnace run all the time to circulate the air.

I will also have a vented gas fire place on the main level, 3 baths with fans (one super duty one in the 1/2 bath on the main floor, and I upgraded the two fans in the full baths upstairs to a quieter, more efficient model but I did not note the CFM's, only remember being told that they were a lot more efficient and clearing out a room of odour much quicker). The hood exhaust over the stove will be 170 cfms.

My windows (I face NNW) in the front of the home will be a triple pane casement window with two low-E coatings. The rear of the house (which contains the most windows) will be a double pane casement with sunstop and Low-E.

The basement is about 1000 sq. feet. I plan on developing the basement in the future. My zones will be basement, Main floor, Bonus room (over the garage with a vaulted 16 foot ceiling, floor will be over garage, gabled roof will run about an R-25 insulation) and the rest of the second floor (Laundry room, Ensquite/Master bedroom, two other bedroom and bathroom + hallway) with 8 foot ceilings and the insulation in the roof will be R-40. The walls are all R-20. The basment and main floor will have 9 foot ceilings.

I need the humidifier for the home. Even without the hardwood, my 3 year old son and wife both get some nasty nose bleeds in the winter. After upgrading my current home for last winter, and installing a humidifier, the instance of nose bleeds went down. My new triple pane windows I have installed on my old/current home hardly showed any condensation. I have a large bay window, plus sliders in the basement, that weren't upgraded. I had to use a blow dryer and a steel spatula to get the ICE off those windows (tells you how air tight and insulated my current home is - isn't that sad). My fault though - my humidifier is a manual adjustment and I had forgotten to change the setting during a particular wicked cold snap.

So, for my new home, I want to obviously have a solid 40% humidity in the home, even during particularly cold days, without having any moisture buildup. So I upgraded the windows all around (even the ones in the doors)and though I would look into the HRV's.

Your comments are very informative - a bit confusing for a layman like me, and I will be re-reading them a few times, but based on what you said, and what my contractor was telling me (oh - no shopping, this is the company my builder uses and I can't use anyone else) I am starting to see what it all entails. My contractor was also mentioning to me the bathroom fans going back down to the electronic HRV as you did, and that certainly is part of the cost. The contractor seemed to think with our climate, venting the bathroom / range hood air directly outside would be best, and using the 'passive' HRV with the exhaust of the expelled warm air of the furnace to warm up the incoming air would be best.

Carmak, now that you have more information, would you still go with the 'electronic' one and have all the expelled air from the home go through it, dehumidify, warm the incoming fresh air, then go through the furnace and into the home, or just go with the passive one?

I just want to make sure I do what's best for my family to remain comfortable in the home, the wood to not dry out, and of course to use a little energy as possible. I only have one shot at this :)

Thanks for your input!!!!!

Hoyme is out in Camrose, they make a motorless air exchanger which I was talking about, when I was refering to the Passive one.

I worked in Calgary for several years in the early 90s and I do not remember Edmonton getting too many Chinooks, but I do remember that Edmonton can get as cold if not worse than Winterpeg.

I can see you are trying to get even with me for making you read the long posts but how about a summary, I think my brain is confusing your exisiting and yet to be built home.

Answer this first, is the new home going to be 2800 square feet plus a 1000 square foot basement?

[drk]

Is an HRV and ERV really worth it?

[Carnak]

Originally posted by kpt_krunch
Carnack - thanks very much for taking the time to explain it so thoroughly. My apologies for not providing all the info, but you sure did cover all the bases.

I guess I see this device as a filter of sorts as the air comes in, and the plus is that the exhausting warm air from the furnace (which is vented out anyway) will warm up the incoming filtered air and thus allowing my furnace to not work as hard to heat up the air.

Hoyme also made one of these passive HRVs,and I made my passive comments based on that.

Here is the Hoyme one, http://www.hoyme.com/airx.html I gave a link to it before.

Being that Hoyme is in Camrose and you are in Edmonton, I now have a strong gut feeling that the passive system you have been quoted on is a Hoyme.

Here is my problem with this passive system. I have seen multiple schemes, in commercial and industrial applications where, air and in some cases water, leaving a heated space, gets heated up before being expelled from the building in order to have more heat energy available to transfer to incoming air through a heat exchanger.

Every time this happens energy ends up being wasted as the exhaust, after it transfers heat to the outside air, is still relatively warm when it leaves the heat exchanger. IMHO, this strategy inherently wastes energy. Better to heat the air when it comes in and use only as much energy as needed. The HRV uses the room temp heat from the exahust only. The passive one uses furnace heat twice!

Think about it, you are heating up air that you are exhausting, this is hot air off of the furnace discharge.

If you are putting in a new high efficiency furnace, 90%+ efficiency, that vents with plastic pipe, you would be better off having a hoyme motorized damper open and have an exhaust fan turn on at the same time, whenever the furnace fired.

The passive system will use a LITTLE less energy than that, it does recover some energy and legally circumvents codes where HRVs are required. Alberta has the cheapest energy costs in Canada so I doubt HRVs are code required there.

So if the goal is IAQ, with lowest installed costs, put in the hoyme intake damper interlocked with an exhaust fan.


Originally posted by kpt_krunch

I realize it is very hard to explain this when you can't see the home design. Lets start with where I am - the dryest area in Canada - Edmonton, Alberta (well, east of Calgary is the driest I guess, but all of Alberta on a whole is very very dry in the winter). Our winters are not as severe as they are east of us in the prairies (Saskatchewan and Manitoba) but they're certainly not pleasent either.

I will have about 800 sq feet of hardwood on the main floor. We could have gone a two furnace route, but I may want to add A/C for the summer (all 2 and 1/2 months of if it :)) and with one furnace and the home zoned I thought would be the better way to go. I was all set to go with what I have currently - which is hoyme dampers electronically controlled on my combustion air and fresh air intakes (I have two furnaces - both Infinity, one high, one mid in my current home) so they only open when the furnace calls for heat. Since my new home is a much tighter construction, the need for a constant fresh air supply is greater. I plan on letting the furnace run all the time to circulate the air.

I will also have a vented gas fire place on the main level, 3 baths with fans (one super duty one in the 1/2 bath on the main floor, and I upgraded the two fans in the full baths upstairs to a quieter, more efficient model but I did not note the CFM's, only remember being told that they were a lot more efficient and clearing out a room of odour much quicker). The hood exhaust over the stove will be 170 cfms.



The famous line "But it is a dry cold". Once you are down well below freezing, its always a dry cold, does not matter where you live.

I have spent some time off of the White Mud Drive and it gets cold up there in Edmonton.

Some Edmonton Design conditions

Winter design temp -32C ---> -26F
Summer Design Temp +28C ---> 82F

54 degrees north latitude ( source of slogan 54 40 or fight!)

Celsius Degree days based on 18C(64.4F) 5782, Degree Days based on 65F will be close to 11,000.

Degree Days are proportional to how much fuel you need for a heating season. The bigger the number the more fuel you will burn.

Altitude, it's a lot lower than Calgary, maybe about 2200 ft.

Calgary gets nearly as cold but because of the Chinooks there are less degree days.

I worked for an OEM in Calgary for about 3 years in the early 90s and before I left Alberta I did some piecework, new construction installs in some NW Calgary subdivisions and found that the furnaces were typically well over sized.

I also tried to sell some AC there, but the only people who would have it installed were those who moved there from Ontario.

I am certain that you must have sealed vapour barriers required by code there. You will not need a humidifier in that new home, in fact you will have too much humidity and window condensation problems if you do not ventilate.

That fresh air intake system to your return air, will over dry your home, then you end up adding a humidifier. You use energy to lower the humidity, then you add humidity back. This is analogous to running the furnace and the air conditioning at the same time.

I hope your furnace will be a high efficiency one with its own combustion air piped right to it. Likewise that gas fireplace should be direct vent as well. If the water heater is gas, then I would get a power vented one that vents out the side wall with plastic pipe. There will be no way then for spilling products of combustion.

I would still install bathroom fans ducted directly outside to get rid of odours in a hurry.

Running these fans intermittently, without a dedicated make up air fan will not be a problem. IF you install a big inline fan, like 300 CFM, in that ensuite, then that would be problematic.

Likewise you mention a range hood and it could exhaust as much air as say your clothes dryer. You could also have a BIG central vac system.

So you could have a problem with a SINGLE big exhaust applaince running or two such as the range hood and dryer running at the same time.

By a problem I am implying that there maybe be a radon risk in Edmonton, or some funny smelling stuff could be getting sucked in.

A six inch Hoyme damper interlocked with some of these bigger appliance systems, that would open and let some fresh air into the unfinished basement, away from any water pipes, would take care of these intermittent large negative pressure situations.

If you want to circulate the furnace fan all the time consider a couple things. With a constant supply of outside air, the air coming out of your registers, when that furnace is NOT FIRING is going to be significantly COLDER than room temperature and will feel drafty.

If you want to circulate air all the time, you may also want a furnace with an ECM motor as they can allow some very low speed. Maybe the Carrier has this feature, but I know that the Rheem Modulating furnace, available from ECCO Heating Products does so too, and it goes to very low speed for cicrculation when the furnace is not firing.

PS ECCO was distributing Rheem when I left Canada in the late 90s.

You will not get any more comfort than you can with that RHEEM MODULATING FURNACE, as long as it is below freezing out, there will ALWAYS be some warm air coming out of the registers. It is very efficient and nothing beats its comfort level. NOTHING. Especially if you want that constant circulation.

QUOTE]Originally posted by kpt_krunch

My windows (I face NNW) in the front of the home will be a triple pane casement window with two low-E coatings. The rear of the house (which contains the most windows) will be a double pane casement with sunstop and Low-E.

The basement is about 1000 sq. feet. I plan on developing the basement in the future. My zones will be basement, Main floor, Bonus room (over the garage with a vaulted 16 foot ceiling, floor will be over garage, gabled roof will run about an R-25 insulation) and the rest of the second floor (Laundry room, Ensquite/Master bedroom, two other bedroom and bathroom + hallway) with 8 foot ceilings and the insulation in the roof will be R-40. The walls are all R-20. The basment and main floor will have 9 foot ceilings.

I need the humidifier for the home. Even without the hardwood, my 3 year old son and wife both get some nasty nose bleeds in the winter. After upgrading my current home for last winter, and installing a humidifier, the instance of nose bleeds went down. My new triple pane windows I have installed on my old/current home hardly showed any condensation. I have a large bay window, plus sliders in the basement, that weren't upgraded. I had to use a blow dryer and a steel spatula to get the ICE off those windows (tells you how air tight and insulated my current home is - isn't that sad). My fault though - my humidifier is a manual adjustment and I had forgotten to change the setting during a particular wicked cold snap.

So, for my new home, I want to obviously have a solid 40% humidity in the home, even during particularly cold days, without having any moisture buildup. So I upgraded the windows all around (even the ones in the doors)and though I would look into the HRV's.
[/QUOTE]

Your new home does not have to be as dry as your present home and YOU DO NOT NEED A HUMIDIFIER TO DO THIS.

It sounds like your home then is 2808 square feet with a 1000 square foot basement, typically 9 foot ceilings, with a bonus room with a ceiling that vaults up to 16 feet high.

You need someone to calculate the heat loss and gain of your home to CSA F280 Standard. If that house was being built in Thunder Bay, similar winter climate as Edmonton, with the same insualtion levels, I would guess that the heat loss would be in the range of 65,000 to 80,000 Btu/hr WITH AN HRV. I do not have your exact plans in front of me so I cannot be specific.

I noticed you posted a model number MVP-120 and if that is a 120,000 Btu/hr 90% furnace it is over kill. Bigger is not better for fuel efficiency, comfort or heat exchanger life.

I would assume then your house has about 3 bedrooms, 3 bathrooms, a ktichen, a dining room, a living room, the bonus room and an unfinished basement to be devolped later so you will need a ventilation system that as a minumum can move at least 170 CFM.

You can do this several ways.

You wire your range hood, or a couple bathroom fans to a dehumidistat to turn on when humidity rises too high. You then either open a window to let air in or have a motorized damper open up to let air in. Your furnace is going to have to burn gas to allow for the extra heat loss.

In the dead of winter to heat that air to room temperature of 70 F when it is -26F outside, your furnace has to add an additional 17,626 Btu/hr to this air.

The HRV recovers 65 to 70% of this loss, so without an HRV your heatloss would be in the range of 76,500 Btu/hr to 91,500 Btu/hr. A 14 to 18% increase in your peak heat loss and your yearly fuel bill.

I do not see the Passive system as being much better than a fresh air intake to the return. You are blowing out hot air, and you still have to heat up the fresh air after the fact.

Like I said before, the first winter after construction, that HRV is going to work hard to dry out the sheet rock mud, and the mositure contained in all the new materials. The same is true of all ventilation systems, they will be on all the time to get rid of that new construction moisture.

So your ventilation system should respond to humidity rise no matter which one you put in.

With the motorized HRV, you can have it ducted to draw air from the bathrooms and the kitchen. The controls can turn on the HRV on a rise in humidity, to draw humid air from the most humid areas of the home, in order to effectively control humidity.

You can do the same thing with a bathroom fan or the range hood, just the HRV can get it from all the humid areas at the same time, and uses the least amount of energy to heat to warm up that fresh air.

Running that HRV or any ventilation system of a similar CFM rate,intermittently in response to rising humidity, will give you good IAQ.

If you want to maintain 40% RH for those hard wood floors, you really need to talk to your window suppliers.

At 70F and 40% RH, the indoor air is looking for an inside surface that is 44.6F (7C) or cooler to condensate upon. How warm will the inside glass and window frames be when it is -32C outside?

AT 64F and 40%RH, the indoor air will sweat if it touches something 39.3F or 4C.

How to keep the windows warmer? Keep thermostat setting higher, avoid bay windows, open the curtains, and or buy better windows.

I would consider triple pane, low e, with argon, with the frames/glass spacers having thermal breaks.

QUOTE]Originally posted by kpt_krunch

Your comments are very informative - a bit confusing for a layman like me, and I will be re-reading them a few times, but based on what you said, and what my contractor was telling me (oh - no shopping, this is the company my builder uses and I can't use anyone else) I am starting to see what it all entails. My contractor was also mentioning to me the bathroom fans going back down to the electronic HRV as you did, and that certainly is part of the cost. The contractor seemed to think with our climate, venting the bathroom / range hood air directly outside would be best, and using the 'passive' HRV with the exhaust of the expelled warm air of the furnace to warm up the incoming air would be best.

Carmak, now that you have more information, would you still go with the 'electronic' one and have all the expelled air from the home go through it, dehumidify, warm the incoming fresh air, then go through the furnace and into the home, or just go with the passive one?

I just want to make sure I do what's best for my family to remain comfortable in the home, the wood to not dry out, and of course to use a little energy as possible. I only have one shot at this :)

Thanks for your input!!!!! [/QUOTE]

You are welcome, I would install the HRV if it were my house. I escaped the 40 below zero scenario seven years ago, but I still know it well.

There could be a lot of posts on this subject from people in milder climates who up until this winter will not have had the opportunity to truly appreciate high fuel bills that people in Canada have endured since time began, so if you have any more questions, please feel free to use the email address in my profile.

[Edited by Carnak on 09-17-2005 at 12:21 PM]

[Carnak]

krunch

Companies like State sell direct vent water heaters that use no draft inducing fans. You have to install them against an exterior wall, with a safe place to vent on the outside. You cannot have opening windows near them.

They can be a challenge to install.

[bpas]

Carnak I would like to thank you for all the valuable information. I am building a home in Calgary and wanted an HRV. I had asked about one of the assuming it would be a motorized one and was recomended one of the passive ones, probably the Huyme one you were talking about. We are building a home with an 1900 sq ft basement and 3500 sq ft of living space on 2 floors. We are planning on triple glazing 2 coats of low e for windows. 4 inches of spray polyurethane foam in the walls and 7 inches of it in the attic. We would like an energy efficient and healthy home. We are planning on using in floor radiant heat for the basement and 1/3 of the main floor with tile. The rest of the home will be forced air. We plan on a high efficiency boiler with 2 air handling units with fan coils. We plan on running air handling units with high efficiency motors at low speed and with a lower water temperature for comfort and energy efficiency. From what I have gatherd from your posts you feel that a mechanical HRV will be much more energy efficient than the passive one. Could I assume this would be even more so with an energy efficient home? Do I assume correctly that if it is passive I would be bringing in constant outside air if I am running my fan almost all the time? If the mechanical ones are almost triple the cost is the payback for long term energy savings there? I assume I would need 2 of the Hrv's one for each air handler so it is quite a difference in the installed cost. On a different note I read your experience in Calgary was the furnaces were quite over sized. How do I prevent this from happening? If I am paying a lot more to have a really air tight, insulated home I would like to save some money on my furnace equipment cost.

Thanks for your help

[Carnak]

bpas, I hope you truly are in Calgary and not Ohio.

Try these guys http://www.hrai.ca/ and see if they can reccomend a contractor in your area who is certified in residential mechanical ventilation and certified to do heat loss calculations to CSA F280 standard.

The contractor should also have some training and certification on infloor heating by manufacturers such as Wirsbo or Kitec(IPEX). I hope you put some insulation under the slab and around the edges up all the way to grade.

With a passive HRV, unless you install motorized dampers, every time the air handler or furnace fan runs it will be exchanging air.

I am not familiar on the R-values of the foam you are using is it blown in stuff or the pink or blue sheets. I am rusty as to what TransAlta (or maybe Fortis?) and the gas company charge out there now a days.

I would recommend an HRV. Flair, Lifebreathe, vanEE make good stuff.

For air tight place in thunder bay, R-22 walls, R-40 ceilings and good windows I would guess the heat load with an HRV to be in the range of 92,000 to 110,600 Btu/hr based on you having an HRV.

You may want some fresh air supplied to the radiant heat zones, With a high side wall discharge.

A boiler, 90% efficient with with a 105,000 INPUT would have a 94,500 OUTPUT

The sizing for infloor heating is a little different, you can feel comfortable at lower temps, the air does not stratify as much. Wirsbro has good load sizing software.

You could search and contact Wirsbo, they may be able to recommend a contractor to you as well.

You want the output to meet your heat load. Boilers tend to get oversized to compensate for losses in the piping for baseboard rads, which you do not have.

Whatever your heat load is, the boiler OUTPUT should be the smallest one with enough output to meet you heat load. It could probably generate lots of domestic hot water for you as well if you used an indirect water heater.

[Carnak]

R2000 homes would have even a lower heat loss. The R2000 concept was not that popular in Alberta but you may wish to follow this energy efficient and green building system in your own home.

[Carnak]

Without floorplans bpas, can't say what your ventialtion rate should be, could be over 240 CFM, may be a little much for a single residential HRV.

Could be two smaller ones, or a small commercial one for one unit.

[bpas]

Thanks for the Quick reply

The polyurethane foam supposedly has an R8 per inch while forming an almost total house seal as far as air infiltration. We do have 2 inches of the blue underneath. My understanding is that we'll be far more energy efficient than a R2000 home. Are you saying that if a damper is installed the passive one will work ok by only opening when needed? I guess the question then is how would it know when it was needed.
The way it was explained to me was that with having the variable speed motor in the furnace running most of the time what the passive one lacks as far as heat recovery efficiency compared to the motorized ones it gains by not using electricity to run it's own motor. Therefore it is almost the same efficiency over all. It did sound logical to me at the time. Perhaps those figures were arrived at with a passive hrv that didn't run as frequently. Just to clarify, depending on what my ventilation rate is I could get by with only one HRV? I don't mind spending the extra money for a motorized one as long as it will perform better enough over the passive one both in saving energy and giving me a healthier home that I see a payback in my pocket eventually and am healthier.

Thanks

[Carnak]

You sound very well insulated. Your heat load could be lower than my guesses then.

The motorized HRV one will outperform the passive one, you are going first class all the way, don't stop now.

There are single commercial HRVs that can easily serve your home.

Typically the HRVs out there seem to be 120, 180 , maybe 225 CFM. It is possible that one of these residential models would work. To meet say an R2000 ventilation rate with a single HRV, I would need to see the floor plans as the number of habitable room factors in.

I mentioned a vent rate of 243 CFM before, which was based on the volume of the home. This could be out of the range of a single residential unit. Been overseas for 7 years now. Maybe Lifebreathe has a resi one that can do upwards to 300.

Posters like Collin and Doc Hvac out of BC are big on HRVs as well, keep an eye out for them, they are more current on the latest model changes. Doc is a good guy, he just has tunnel vision and can only see Lifebreathe. :)


[Edited by Carnak on 09-19-2005 at 12:15 AM]

[teddy bear]

Originally posted by Carnak

Originally posted by teddy bear

Originally posted by kpt_krunch
Alright - I met with my h-vac contractor today. I'll be getting the Infinity MVP120 for a 2808 + Basement sq.foot home. Four zones with Infinity Zone control, flow-through humidifier, and an HRV System.

I guess there are two types of HRV's from Carrier, one is an electonric one with two fans, and one is a passive one. The Electronic one will run about $3500.00 installed (this is Cdn money) and the Passive one will be $650.00.


tb quote. I sell them but rarely. Usually for electric heated homes at +8000 degree days and high occupancy.
ring the summer during low/no cooling load. Careful you may spend 10-15 k and still end up with a wet house during a wet cool summer. TB

So with today's rising energy prices maybe the HRV deserves a little more respect than the disdain you seem to show it. They save more money than a dehumidifier Nazi realizes :)

Southern Ontario may be 8000 degree days or a little less, Northern Ontario and a lot of western Canada is 10,000 to 12,000 degree days.
Berkley labs need to open a branch up in Saskatchewan.

[Edited by Carnak on 09-16-2005 at 05:07 PM]
I suggested HRV with +8000 DD. Remember HRV adds to natural ventilation.
those +100 cfm rates from an HRV added to natural will over ventilate most homes. I am hoping for a "job title change". I didn't mind "web dehu peddler" but would prefer "dehumidifier Czar" to your suggestion.

[Carnak]

LMAO, NAZI was insprired by Seinfelds "Soup Nazi"

The natural infiltration rate will be wanting, be big moisture problems without ventialtion. The ballpark heating loads include natural infiltration plus the effect of the heat loss due to the HRV supply air.

After the first winter I agree that the HRV ventilation rate will over ventilate with respect to making the home too dry, that is why I suggest operating them intermittently on a rise in humidity.

[dunburn]

Carnak -- you're recommending that an HRV operate only on the rise of humidity and intermittently...

Most controls / dehumidistats I have read about online kick-in only when a the highest percentage of humidity is reached, thereby ensuring that humidity remains below that level.

What type of dehumidistat or other controls would you recommend to ensure that houses are not over-ventilated (causing problems - drying out a house), and that the HRV only operates intermittently?

---------
Seems to me it's all about balance - HRV (Ventilation), Humidification, heating, and cooling...

[Carnak]

Some manufactureres such as Flair/Venamr/van EE will have nice proprietary controls.

You can set these systems to run continuously on a 'low' speed, and then on a rise in humidity, they will switch to high speed, at rates typical as I have been describing, until humidity is lowered below a set point.

Some systems will switch to high speed on a rise in CO2 as well however with people exhaling both H20 and CO2, if you control for one, you indirectly control for the other.

When I describe intermittent operation, I am talking about a home that has already been through a winter and lost the moisture of construction.

Depending on how cold it is where you are, the schemme of constant low speed ventilation could over dry the home.

Again, proprieatary controls can allow the ventilation system to be off, until there is a rise in humidity. This is a cold weather scenario, where too much indoor humidity results in condensation on windows.

In the intermittent mode, when humidity rises above a set point, the system will turn on, on high speed, and exchange air until humidity drops down below the set point, then the systems shuts off.

Other manufacturer's may not have eleaborate controls, but they can be used with dehumidistats by Honeywell or Penn/Johnson and will also operate intermittently, on a rise in humidity.

They will turn the syatem on when the humidity exceeds a setpoint and then run until humidity has fallen below a setpoint by so much. This differential may be fixed into the control, or could be adjustable.

[dunburn]

This is good information... I doubt the original requester, nor most others, want to over-ventilate a house -- and cause dryness issues.

Do you know if there exists any controls that would increase ventilation and decrease the call for humidity based on both 1) internal temperature and 2) external temperature?

Reason: if you use a programmable thermostat for heating and cooling, you would also need something to allow you to ventilate the home to decrease humidity in a cold climate such as Canada -- whenever you drop the temperature at night, yet increase humidity when the outside temperature rises (or the opposite when temperature drops).

[rich pickering]

bpas, try Healthy Heating, it is from Storefronts, right side of page.Robert Bean is from Calgary.

And for what it's worth, over here in Saskatchewan, HRV is the only way to go.

[cmcgale]

I know this probably isnt the place to post this but. I am a 2nd year sheet metal mech that needs some help connecting C/A and F/A Hoyme dampers to my CVA90 system. I have a Infinity stat connected and as I can tell all standard 24V functions (R,W, etc) are terminated when this stat is connected. Do anyone of you know how to wire up Hoyme dampers to the Infinity system?

Chris,
Vegreville, Alberta

[Carnak]

You must of used a little initiative and searched "Hoyme" to find this old thread.

most of the posters in here are American so they will not be familiar with the Hoyme Dampers

I do not know anything about Carrier infinity so you are SOL with me.

Once you get a few posts under your belt apply for professional memebership, then the guys may help you with the technical questions.

You can try reposting the question in a new thread perhaps, give a link to Hoyme's wiring diagrams so the guys can see they are straight 24 volt and have end switch options.

Hoyme shows how to wire in the CA dampers already on their site, you just need a 24 volt signal to open up zone dampers from the inifinity control

[HMI Hoyme]

Hello Chris (cmcgale),

Cliff Hoyme here from Hoyme Manufacturing Inc.

To answer your question on using the Infinity Systems with Hoyme Combustion Air Dampers:

The Hoyme Combustion Fresh Air Damper (CA) has four wires: two are connected to the 24Vac supply to close the damper and two are connected in series with the signal going to the gas valve to cause the damper to open before the appliance fires. The Infinity System exposes the “R” and the “C” to provide the 24Vac supply to keep the damper closed. The signal required to open the damper is found in the circuit leading from the last proving switch to the “TH” on the gas valve. More information can be found on the Hoyme web page at www.hoyme.com (http://www.hoyme.com).

If you have any other questions about this or any of the other products we manufacture please do not hesitate to contact us here at the factory at 1-800-661-7382. or e-mail us at hoyme@hoyme.com

-Cliff

[Carnak]

Hello Chris (cmcgale),

Cliff Hoyme here from Hoyme Manufacturing Inc.

To answer your question on using the Infinity Systems with Hoyme Combustion Air Dampers:

The Hoyme Combustion Fresh Air Damper (CA) has four wires: two are connected to the 24Vac supply to close the damper and two are connected in series with the signal going to the gas valve to cause the damper to open before the appliance fires. The Infinity System exposes the “R” and the “C” to provide the 24Vac supply to keep the damper closed. The signal required to open the damper is found in the circuit leading from the last proving switch to the “TH” on the gas valve. More information can be found on the Hoyme web page at www.hoyme.com (http://www.hoyme.com).

If you have any other questions about this or any of the other products we manufacture please do not hesitate to contact us here at the factory at 1-800-661-7382. or e-mail us at hoyme@hoyme.com

-Cliff


I thought that was you Mr. Cliff, nice chatting to you the other day on the 8" dampers and your interface