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  1. #1
    Join Date
    Jun 2007
    Location
    Bucks Co PA
    Posts
    364

    House Dehu- Fresh Air- Heat Recovery?

    I'm coveting a two stage heat pump, but the wife sees too many $$$. (styling is more important to her than function)

    My main problem is humidity 60 to 75%.

    Therefore, I'm looking at a Ultra-Aire whole house Dehu until I can persuade the wife a new heat pump is desirable. (BTW Ultra-Aire sent a list of dealers most of which are far away). I figure a whole house Dehu will give comfort and reduce the need for AC till it gets hotter.

    My question, I hear so much about indoor pollution and I read that the Ultra-Aire can be vented from outdoors, but won't that increase operating costs by bringing in outdoor humidity ?

    I also read on this forum, that CO2 can be an indication of indoor pollution. Do most HVAC techs have a device to read CO2 ? I know they are expensive devices.


    BTW Anyone see many heat recovery units with out door ventilation ?
    .

  2. #2
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,331
    your local a/c contractor is a good canidate to install the Ultra-Aire in your home. UA is simple for knowledgable contractor. Most UA dealers have been introduced to the unit via inovative customers.
    Despite what you read, full featured a/c/hp will not control humidity during low/no cooling loads and high humidity. If you are getting adequate fresh air into your home, you need 20-60 lbs. per day of dehumidification to maintain <50%RH in your home. On a hot day, your a/c will remove this moisture. Fresh air is getting into your home naturally on windy days. Infiltration is one of the reasons your humidity maybe high now. A home should be tight enough to avoid excess infiltration during cold weather and be short on fresh air during summer. Very tight homes need the ventilating feature. If your home is a leaker, no need for fresh air from your UA. Just use it as a whole house dehumidifier. Homes that need humdification during cold weather are leakers. The should be tighten to the point where no humidification is required. That will save big bucks on heating. But you will need supplemental ventilation during milder temperatures. Not all bad. An air tight home is net energy gain with winter gains. Search "teddy bear" post for additional info. Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  3. #3
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,331
    your local a/c contractor is a good canidate to install the Ultra-Aire in your home. UA is simple for knowledgable contractor. Most UA dealers have been introduced to the unit via inovative customers.
    Despite what you read, full featured a/c/hp will not control humidity during low/no cooling loads and high humidity. If you are getting adequate fresh air into your home, you need 20-60 lbs. per day of dehumidification to maintain <50%RH in your home. On a hot day, your a/c will remove this moisture. Fresh air is getting into your home naturally on windy days. Infiltration is one of the reasons your humidity maybe high now. A home should be tight enough to avoid excess infiltration during cold weather and be short on fresh air during summer. Very tight homes need the ventilating feature. If your home is a leaker, no need for fresh air from your UA. Just use it as a whole house dehumidifier. Homes that need humdification during cold weather are leakers. The should be tighten to the point where no humidification is required. That will save big bucks on heating. But you will need supplemental ventilation during milder temperatures. Not all bad. An air tight home is net energy gain with winter gains. Search "teddy bear" posts for additional discussion. Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  4. #4
    Join Date
    Jun 2007
    Location
    Bucks Co PA
    Posts
    364
    Quote Originally Posted by teddy bear View Post
    your local a/c contractor is a good canidate to install the Ultra-Aire in your home. UA is simple for knowledgable contractor. Most UA dealers have been introduced to the unit via inovative customers.
    Despite what you read, full featured a/c/hp will not control humidity during low/no cooling loads and high humidity. If you are getting adequate fresh air into your home, you need 20-60 lbs. per day of dehumidification to maintain <50%RH in your home. On a hot day, your a/c will remove this moisture. Fresh air is getting into your home naturally on windy days. Infiltration is one of the reasons your humidity maybe high now. A home should be tight enough to avoid excess infiltration during cold weather and be short on fresh air during summer. Very tight homes need the ventilating feature. If your home is a leaker, no need for fresh air from your UA. Just use it as a whole house dehumidifier. Homes that need humdification during cold weather are leakers. The should be tighten to the point where no humidification is required. That will save big bucks on heating. But you will need supplemental ventilation during milder temperatures. Not all bad. An air tight home is net energy gain with winter gains. Search "teddy bear" post for additional info. Regards TB
    Thanks for the reply TB.
    My house was built in 1988, and I had a "energy" company seal the house as it was built and added insulation to the walls which are about R-20-22. Attic is about R-38.

    It is 2600 sq ft, and I do need humidification in the winter, but I do not need to start the furnace till <52* OD unless it is very windy. The high humidity and relative low heat loss leads me to believe it is tight, but humidity is needed in winter.

    I have a HVAC contractor referred to me by someone on this board, but when I called to ask about the Ultra-Aire a girl answering the phone said they only sell April Aire and gave me a "humidifier" model. Maybe I should call back and ask for the owner.


    BTW, will the average HVAC tech have access to a CO2 measuring device ?
    .

  5. #5
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,331
    Yes, talk to the owner. Or there is a bright, energitic a/c contractor near you who is looking an opportunity to serve. As you see by the discussions on this site, traditions are hard to break. Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  6. #6
    Join Date
    Jun 2004
    Location
    4H: Hot, Humid Houston H.O.
    Posts
    3,304
    If you want to persuade the contractor that Aprilaire is not your preference, tell them about the wattage vs. pints/day difference. As I remember the UA-100 series is rated around 100 pints/day and draws about 7 amps. And the newer UA-XT150H is rated around 150 pints/day and also draws about 7 amps. There are some intermediate Thermastor models which are not equally energy efficient. Last time I looked, Aprilaire had one model rated around 90 pints/day and drawing about 10 amps.

    I am ga-ga about being efficient in certain ways, to the point of being emotional not rational, this energy efficiency really pushes my hot button personally. But if you choose to be rational, you ought to estimate the actual cost of running and if Aprilaire is any cheaper, see what the payback time is.

    You might be able to persuade your wife via 1st trying a cheaper dehu bought from a big box store. If she sees that is *somewhat* effective in making the home more comfortable, then you can sell the idea of a bigger, better and less energy intensive version of that benefit. I accidentally did this experiment with my own family, my wife surprisingly really likes the benefit of a Thermastor Santa Fe RX in the laundry room.

    >>Ultra-Aire can be vented from outdoors, but won't that increase operating costs by bringing in outdoor humidity ?

    Think you can count on the UA to do its work on outdoor air, so you cannot really say it brings in outdoor humidity. What it intakes is outdoor humid air (if you ventilate) and what it delivers is dry air. There is an energy cost associated with this benefit. Try looking at it this way: it would be even more energy efficient to turn off the AC entirely and open the windows, but that's not quality of life according to most people.

    >>I also read on this forum, that CO2 can be an indication of indoor pollution.
    >>Do most HVAC techs have a device to read CO2 ? I know they are expensive devices.

    I am a homeowner in S.Texas which is far from you, but around here most HVAC techs can be counted on to have a truck and some basic tools and knowledge. I find that if I ask one to measure static pressure, he likely will tell me he doesn't have the Magnahelic gauge to do that. A CO2 measuring device is far more exotic than that.

    >>BTW Anyone see many heat recovery units with out door ventilation ?

    Any HRV or ERV would qualify for that. Can you answer whether many of your neighbors have an HRV or ERV? They sell quite a few for use *somewhere* in the country.

    Hope this helps -- Pstu

  7. #7
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    With your indoor humidity ,you have an issue of somekind.

    Maybe infiltration ,but sounds like it was built tight.

    Rain and overcast here,the wife cooking and the humidity has crept up to 52&#37; on the sysstem that serves the kicthen,the other one is at 48%.Carrier Infinty on one and Thermidistat on the other.

  8. #8
    Join Date
    Jun 2004
    Location
    4H: Hot, Humid Houston H.O.
    Posts
    3,304
    What Dash said, first of all. It would be a shame to get a dehu as a fix, and leave another gross problem unsolved. My S.Texas house without any kind of separate dehumidification would be able to get approximately 55&#37; RH at 78 degrees, with outdoor air around 95F and 72 dewpoint. Wherever you are in PA, the climate is likely not as adverse.

  9. #9
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Still rainey and washer and dryer running for hours ,now 50% and 47%.

  10. #10
    Join Date
    Apr 2002
    Posts
    11,808
    Quote Originally Posted by Jack2007 View Post
    I'm coveting a two stage heat pump, but the wife sees too many $$$. (styling is more important to her than function)

    My main problem is humidity 60 to 75%.

    Therefore, I'm looking at a Ultra-Aire whole house Dehu until I can persuade the wife a new heat pump is desirable. (BTW Ultra-Aire sent a list of dealers most of which are far away). I figure a whole house Dehu will give comfort and reduce the need for AC till it gets hotter.

    My question, I hear so much about indoor pollution and I read that the Ultra-Aire can be vented from outdoors, but won't that increase operating costs by bringing in outdoor humidity ?

    I also read on this forum, that CO2 can be an indication of indoor pollution. Do most HVAC techs have a device to read CO2 ? I know they are expensive devices.


    BTW Anyone see many heat recovery units with out door ventilation ?
    .

    I have been yapping about CO2 sensors but I do not think the typical tech will have one.

    It sounds like you do not have AC at present is this the case?

    A small dehu in the basement will make a difference. I used to circulate basement air in my old home in Canada through out the house during the summer. I ran a Kenmore 40 pint dehumidifier down there, it kept the huimidity under 60%. Keeping the windows closed and the drapes drawn during the day kept the heat out, so it was bearable without central AC

  11. #11
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,315
    Quote Originally Posted by dash View Post
    Still rainey and washer and dryer running for hours ,now 50% and 47%.
    The other morning I had 73 degrees outdoors, with 79% relative humidity. Indoor was 74/48%, and that after a morning shower. Cool, wet weather, for as short as it lasted (hit low nineties later in the day), and single stage central a/c kept humidity below 50%.

  12. #12
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,870
    Came home from a birthday party for a nephew. Stat set to 74, it was at 54%RH, started dishwasher when we left, dang, just didn't feel good. Set stat to 72, its now 73, and the RH is down to 50%, starting to feel much better inside now.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  13. #13
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,331
    Quote Originally Posted by shophound View Post
    The other morning I had 73 degrees outdoors, with 79% relative humidity. Indoor was 74/48%, and that after a morning shower. Cool, wet weather, for as short as it lasted (hit low nineties later in the day), and single stage central a/c kept humidity below 50%.
    No cooling load and humidity stays low while high outdoors humidity is high, is a sign of little or no infiltration. If you were getting a air change every four hours, what the indoor %RH be? I think it is a great starting point. Do make-up air ventilation when the home is occupied. During hot weather your a/c will handle it. If there is no way that you can handle a dehu, just don't ventilate during wet cool weather. Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

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