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  1. #1
    Join Date
    Jun 2003
    Posts
    120

    dehumidifier questions

    Ok, so I have learned that I have some humidity problems in my home (1,100 square foot ranch) in southern New York State. Winter time is fine and summertime is fine. where I have issues is on cooler days or mornings where the dew point is high. For example, last night when I went to bed, the RH was 50%, the ac had been on from the late afternoon through the evening. It seems to do a great job at removing the humidity even though it is a bit oversized.

    However, last night the temp dropped to 62 outside and the RH this morning OUtside is 85%. I had slept with some windows open b/c my AC just would not have run overnight with temps that low.

    The RH in the house this morning is 70%. That has me nervous about mold,etc...


    I do run a dehumidifier in the basement which works great at keeping the entire basement at 50%, I have the drain go directly to my sump, so it runs auto pretty much.

    I have seen some posts about whole house dehumidifiers and the possiblilty of hooking them up to the main return? of the house.

    Are these types of dehumidifiers, sante fe, etc.., that hook up to the duct work easy to find and also are they the type of thing that a homeowner installs?

    I installed the one in the basement, but it was easy, just put it there and hook up a garden hose to it. Not so sure about hooking up to the ductwork though.

  2. #2
    Join Date
    Mar 2004
    Location
    Illinois
    Posts
    6,959

    Look here...


  3. #3
    Join Date
    Jun 2003
    Posts
    120
    Quote Originally Posted by Senior Tech View Post
    Good stuff in there, I have only read some of it at this point. Further question though:

    My central AC when it runs removes humidity fine, so it is only when the AC is NOT running that I need dehumidification. Do the units that you linked to specialize in that type of application or are they more suited to run in conjunction with AC?

    I would want the unit to remove humidity in my living space but also remove humidity in the basement. If this is hooked up to the house return vent, how would it remove humidity in the basement?

  4. #4
    Join Date
    Dec 2006
    Location
    Northern VA
    Posts
    389
    Your problem doesn't really have a yes or no answer or even a 2 page response. A pro really needs to see your home and evaluate what you have and what needs to be done to fix your problem. Without a proper evaluation you can throw a lot of money at a problem and never fix it.

  5. #5
    Join Date
    Jun 2003
    Posts
    120
    Quote Originally Posted by EverettsHVAC View Post
    Your problem doesn't really have a yes or no answer or even a 2 page response. A pro really needs to see your home and evaluate what you have and what needs to be done to fix your problem. Without a proper evaluation you can throw a lot of money at a problem and never fix it.
    I don't know a good pro and I had a bad experience witht the installation of my AC 5 years ago. I know there are good HVAC contractors out there, but I have to find one in southern NY.

  6. #6
    Join Date
    Dec 2006
    Location
    Northern VA
    Posts
    389
    Quote Originally Posted by brewyourown View Post
    I don't know a good pro and I had a bad experience witht the installation of my AC 5 years ago. I know there are good HVAC contractors out there, but I have to find one in southern NY.
    I can understand your pain. Sorry I can't help there. I guess the best advice I can give there is too keep looking. You really need a proper evaluation. Maybe someone on here can suggest someone.

  7. #7
    Join Date
    Jul 2008
    Location
    Ga.
    Posts
    5

    Thumbs up The ultimate in dehumidification

    Regardless of system, regardless of S.E.E.R., regardless of situation. Look up an Aprilaire 1750. Most of the time, if you do not have enough heat load on your house due to trees or weather or what not or some "genius" ovesized your system so it does not have enough run time. An Aprilaire 1750 hooked into the ducts will fix most problems. Down here in Ga. people are just now "catching on" that the Higher the S.E.E.R., the less it dehumidifies. And yes, lets all say it "Bigger is not better!". No I do not work for Aprilaire, Aprilaire works for me! I have a 1850 square foot home on a slab surrounded by trees. I tried a 3 ton then a 2.5 ton. Then i got smart and installed a 1750-NIGHT AND DAY!-Boz
    P.S. To answer the basement question, you can run ducts off of the 1750 to the basement as well. But I would try it on the system first. Remmember the #1 rule in humidity, "HUMIDITY GOES WHERE HUMIDITY IS NOT."

    Quote Originally Posted by brewyourown View Post
    Good stuff in there, I have only read some of it at this point. Further question though:

    My central AC when it runs removes humidity fine, so it is only when the AC is NOT running that I need dehumidification. Do the units that you linked to specialize in that type of application or are they more suited to run in conjunction with AC?

    I would want the unit to remove humidity in my living space but also remove humidity in the basement. If this is hooked up to the house return vent, how would it remove humidity in the basement?

  8. #8
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,258
    Quote Originally Posted by brewyourown View Post
    Good stuff in there, I have only read some of it at this point. Further question though:

    My central AC when it runs removes humidity fine, so it is only when the AC is NOT running that I need dehumidification. Do the units that you linked to specialize in that type of application or are they more suited to run in conjunction with AC?

    I would want the unit to remove humidity in my living space but also remove humidity in the basement. If this is hooked up to the house return vent, how would it remove humidity in the basement?
    The ducted Ultra-Aire or Santa fe only operate when the %RH exceeds the %RH setting that you select. If the a/c keeps the %RH below the setting- no dehu. These unit have a strong fan that can blow into or suck from the a/c ducts while the a/c operates. The attached web site shows a possible method of dehumidifying the home and basement. The fresh aire is optional. Many northern climate homes do not get enough fresh during the summer because of the lack the winter stack effect. The Santa Fe can be connected similar to the UA. As you see there are several brands and sizes of dehu available. Our dehus have been refined for this application for 18 years. They are the most reliable and efficient dehus manufactured. Combining the dehu with your a/c will provide 50%RH throughout your home. Regards TB


    http://new.thermastor.com/Ultra-Aire-65/UA-65_sheet.pdf
    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"

  9. #9
    Join Date
    Jun 2003
    Posts
    120
    Quote Originally Posted by teddy bear View Post
    The ducted Ultra-Aire or Santa fe only operate when the %RH exceeds the %RH setting that you select. If the a/c keeps the %RH below the setting- no dehu. These unit have a strong fan that can blow into or suck from the a/c ducts while the a/c operates. The attached web site shows a possible method of dehumidifying the home and basement. The fresh aire is optional. Many northern climate homes do not get enough fresh during the summer because of the lack the winter stack effect. The Santa Fe can be connected similar to the UA. As you see there are several brands and sizes of dehu available. Our dehus have been refined for this application for 18 years. They are the most reliable and efficient dehus manufactured. Combining the dehu with your a/c will provide 50%RH throughout your home. Regards TB


    http://new.thermastor.com/Ultra-Aire-65/UA-65_sheet.pdf
    So who installs these things? Any HVAC contractor? If you were me and didn't know an HVAC contractor, how would you go about choosing?

  10. #10
    Join Date
    Jun 2003
    Posts
    120
    I have an idea, maybe

    How about this. I have a pretty large vent in my basement attached to the main trunk line of the AC/Heating Ducts. The vent faces down and I use it in winter for a little heat to the basement.

    What if I open that vent up and allow ac to go into the basement as well as the upstairs. In essence I would end up reducing the CFM of the air to the upstairs and thereby making the AC run longer.

    sure, this will cost more and the basement would probably be a little on the cold side, but the AC would run longer and I might get better humidity control?

    What do you think?

    I would have to balance out the air flow a bit upstairs with the downstairs vent open, but if it helped to solve the problem, man would it be worth it.

    Good idea? Bad idea?

  11. #11
    Join Date
    Jun 2003
    Posts
    120
    Also,

    What is cheaper, getting a smaller AC or adding in the whole house dehumidifier?

  12. #12
    Join Date
    Mar 2008
    Location
    Central Maryland
    Posts
    246
    Quote Originally Posted by brewyourown View Post
    What if I open that vent up and allow ac to go into the basement as well as the upstairs. In essence I would end up reducing the CFM of the air to the upstairs and thereby making the AC run longer.

    sure, this will cost more and the basement would probably be a little on the cold side, but the AC would run longer and I might get better humidity control?
    I do that. It knocked a couple percent off the basement humidity, but it was still too high, so I bought another dehumidifier to replace the one that bit the dust last Fall. I still do it now, though, because the dehumidifier raises the basement air temperature two degrees, and we use the basement as a cool play room in Summertime.

    The main problem with humidity in the rest house is that this Spring was cool and rainy, and the A/C just didn't run enough. Even now that Summer is here and it runs plenty, the house is OK but the basement still needs a little help. (Like, I dump a gallon every 24 to 36 hours).

    If you were to go all the way to a whole-house dehumidifier, I would use that opportunity to introduce fresh air venting through it. Oh yeah, that dehumidifier might be Energy Star but it will still cost a little more, and a little more than opening the basement vent.

    -HF

  13. #13
    Join Date
    Jun 2003
    Posts
    120
    well I opened up the basement vent and this afternoon since doing it, I have been getting 40 minute run times with 5 minute off times. I have stat set to 73 degrees and it is 79 degrees outside.

    I think I solved my problem. Humidity was brought down to 50%. We'll see over the next few days if humidity remains at that level though. But I have to believe if I am getting 40 minute run times holding 73 that when the temp outside gets up to lower 90s, it'll basically be sized correctly.

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