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Gerb10 03-26-2013 09:35 AM

Humidity Question
 
I live in a single story ranch with a full unfinished basement. Humidity downstairs is near 70% and upstairs is around 50%. I need a dehumidfier downstairs and a humidifier upstairs. Is there a way to move the humidity from downstairs to upstairs without buying these two seperate devices? My heating/cooling system is a GEO unit on an open loop and I only condition the upstairs until I finish the downstairs, which is years away.

gregzoll 03-26-2013 10:01 AM

It is too high downstairs. It should be at around the same as upstairs. You have some serious issues of either no air exchange from inside to out with the place being too tightly sealed, or a poorly air sealed home.

djlandkpl 03-26-2013 11:23 AM

I can't think of a way without mixing the air between the basement and upstairs which you don't want to do. You wind up conditioning the air in the basement. An energy star rated dehumidifier doesn't cost that much to run. Off the top of my head, I think 50% humidity is a good number for the winter. Too much higher and you can have condensation issues.

Gerb10 03-26-2013 12:04 PM

It just seems so dry upstairs, I run a small humidifier in the bedroom at night to help combat it. Seems like you should be able to somehow use the moist air downstairs to aliviate the upstairs dryness. Dehumidifiers for our size basement typically cost between $200-$300. I just wanted to research this option prior to purchasing a dehumidifier. Thanks for the responses!

gregzoll 03-26-2013 12:12 PM

If it is the basement that has high humidity, you need to seal around the joist perimeter and insulate. You also need to make sure that the HVAC system is able to have a output and return to help keep that space conditioned like the rest of the home. Otherwise, you end up with mold & mildew down there, and wood rot from too high of a humidity level.

djlandkpl 03-26-2013 12:49 PM

Quote:

Originally Posted by Gerb10 (Post 1146212)
It just seems so dry upstairs, I run a small humidifier in the bedroom at night to help combat it. Seems like you should be able to somehow use the moist air downstairs to aliviate the upstairs dryness. Dehumidifiers for our size basement typically cost between $200-$300. I just wanted to research this option prior to purchasing a dehumidifier. Thanks for the responses!

I know it's crazy. I have to do the same. Dehumidifier in the basement, humidifier on the furnace. Once you get the humidity level down to a reasonable level, the unit should not run as long unless you have leakage. Then you should seal as Greg suggests.

You may want to consider two smaller dehumidifiers instead of one depending upon how big a space it is. Also, if the space gets below 50 degrees, you need to get one that will work in cold temperatures. It's been my experience that dehumidifiers don't last long. 2-4 years tops, so don't buy the Cadillac.

You "could" take the basement moisture and move it upstairs but it would be the same as running a dehumidifier and humidifier.
The dehumidifier would take the water out of the air, send it to the humidifier connected to your air handler.

beenthere 03-26-2013 03:37 PM

What temp is your basement and first floor. 50% almost makes it sound like your hydrotherm is inaccurate.

cleveman 03-26-2013 08:14 PM

Yeah, are you sure your hygrometers are accurate? Have you switched them from upstairs to down?

I would beg to differ about a dehumidifier being inexpensive to operate. You may find it less expensive to just open a return near the furnace and a supply on opposite sides of the basement.

how 03-26-2013 09:13 PM

Humidity levels in a home idealy are kept between 30 - 50 %. Why is it so high downstairs????
Does your basement have heating and return air ducts so that the furnace fan can mix the upstairs and downstairs with a low speed fan operation?

cleveman 03-26-2013 09:39 PM

I like my humidity at 55 if possible. Below 45 and your nose starts to crack open and your skin as well. This leaves a super highway for infections to get in your body.

beenthere 03-27-2013 04:23 AM

Quote:

Originally Posted by cleveman (Post 1146636)
I like my humidity at 55 if possible. Below 45 and your nose starts to crack open and your skin as well. This leaves a super highway for infections to get in your body.

The inside corners of your outside walls will be a lower temp then the rest of your house. This is here the humidity will often be the highest. So if you keep your humidity at 55%, those areas can exceed 60% and can cause mold growth.

Fairview 03-27-2013 08:49 AM

What's the problem with conditioning the basement? According to manual J the load is zero on a completely underground basement.

beenthere 03-27-2013 03:30 PM

Quote:

Originally Posted by Fairview (Post 1146885)
What's the problem with conditioning the basement? According to manual J the load is zero on a completely underground basement.

Never seen a Manual J say that a completely underground basement is zero BTU loss.

Fairview 03-27-2013 05:11 PM

Quote:

Originally Posted by beenthere (Post 1147164)
Never seen a Manual J say that a completely underground basement is zero BTU loss.

I probably shouldn't have written zero. Sorry about that.
************************************************** ******

beenthere

09-01-2010, 06:12 PM HVAC Talk


Unless its a real big basement. or has lots of air leakage. A basement doesn't need much heat(completely below grade basements that is).

The ground temp is 55, so you don't have much of a load, and often, some contractors will say no load.

beenthere 03-27-2013 05:33 PM

Quote:

Originally Posted by Fairview (Post 1147259)
I probably shouldn't have written zero. Sorry about that.
************************************************** ******

beenthere

09-01-2010, 06:12 PM HVAC Talk


Unless its a real big basement. or has lots of air leakage. A basement doesn't need much heat(completely below grade basements that is).

The ground temp is 55, so you don't have much of a load, and often, some contractors will say no load.


Not much of a load. But still a load. A 1200 sq ft completely under ground/below grade basement with a ground temp of 55 will usually have a heat loss between 6,000 and 12,000 BTUs.


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