Take the 2-minute tour ×
Home Improvement Stack Exchange is a question and answer site for contractors and serious DIYers. It's 100% free, no registration required.

I just bought a 50 pint dehumidifier for my basement. What humidity level should I aim for? This time of year the outside humidity is very high (over 80%) and we do not have central air. Right now it is set to 55% and seems to be running constantly. Should we keep it running and try and get it even lower than 55%?

share|improve this question
2  
If you have the ability to, you might want to consider discharging it to a drain or sump pit. Most humidifiers have a nipple that you can clamp a hose to, so you won't have to worry about the pan filling and having to constantly empty it. –  Tester101 Jul 26 '11 at 1:23
7  
Without AC, if the windows are open, you'll never win the battle against the humidity. Once the windows and doors are closed, turn it up as much as you want and can stand to pay on the electric bill. –  BMitch Jul 26 '11 at 1:54
    
@BMitch: That is sort of my problem. We don't have AC so all the windows on the 3 floors we live on are open all day and night. The basement windows (and the interior door down to the basement) are closed but that is not stopping much airflow down to the basement. There are 2 large cold air returns from the 1st floor down to the basement and the hardwood floor has no subfloor (or tongue & groove) so air passes right through that as well. –  auujay Jul 26 '11 at 14:01
2  
Well you are trying to dehumidify the outside if you don't stuff up any basement returns to an open-windowed upstairs, caulk around basement windows, and install floor sweeps on cold cellar and basement doors, as well as add weather stripping around doors. I did these things all for cost of what I would pay for electricity in one month on my dehumidifier; now it runs half as much. –  user13966 Jul 12 '13 at 19:09
add comment

4 Answers 4

up vote 11 down vote accepted

30-40% in winter. Otherwise below 60% to keep mold away. Or even below 50% to avoid dust mites.

You can also see this question: Humidity Levels.

share|improve this answer
    
My understanding is that mold will not grow below 65% humidity. –  Steve Jul 16 at 20:32
add comment

I believe the answers above are a bit more realistic than others I've seen. Remember if air outside is 60% RH and the temp is 80°F that would be equal to about 75% RH with with a basement temp of 60°F. Keeping it around 55%-60% will be comfortable and obtainable with a decent dehumidifier.

share|improve this answer
add comment

Recommended humidity levels for human comfort is 30-60%[1]. Plus, in a basement, you want to keep things dry for the sake of the structure. I'd let it run as much as it needs to run.

[1] http://en.wikipedia.org/wiki/Thermal_comfort#Relative_humidity

share|improve this answer
add comment

FYI - I had a musty smell in our 30ft x 40ft basement, (our 35 year old dehumidifier was no longer up to the task.) I bought a new 45 pint dehumidifier. It took away the musty smell just fine but was running all the time. After a few days, I adjusted the humidity setting (from 42% factory setting) to 56% and now it runs only when needed. Smell is gone and all is well.

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.