Can someone please help? I am a small project remodeler who is having a humidity problem in my own home. It has been happening for about 6 years now and I am losing hope that this problem will be solved. I live in Northwest Arkansas. I don’t know of anyone else having the same problems, so I can’t blame it on the weather around here like you might be able to in a more tropical location. None of my neighbors are having the same trouble although they have been dealing with some of the same water issues that I have. I have had probably 30 people try to help me solve this problem, have spent more that $20,000 in “improvements” and only one thing that has done ANYTHING to decrease the humidity is to seal some air leaks between the house and the crawl space. Installing the new windows seemed to increase the humidity a little, although I am unsure about that because I can’t find my records at this point. I know that it did not help any. I do NOT want to run a dehumidifier. I’ve been doing that. I want to figure out what the problem is and fix it.
Humidity is fine when A/C is not needed. As soon as the A/C is needed (temps over 75 for me), humidity shoots up to between 58% to 65%. I have set the A/C at different temps in order to change the humidity level without much success unless I crank it down to something like 62 degrees and it runs continuously. I like it cool in the house and have to have it cool to sleep well. I am having to set it at 67 degrees at night to be able to be somewhat comfortable, but have noticed that I am REALLY comfortable at other people’s houses when it is set at 70 degrees. The air in my house is noticeably damp and mildew is a problem.
The blower motor was replaced sometime near the time of the start of the humidity problem. I can’t remember if it was before it started or after and it’s been checked out by four A/C contractors and found to be working properly. I had someone go into the attic and open the unit to check the temperature of the coil, it is running at the correct temps too (~46 F).
My house is about 1,900 s.f. with a Carrier 58RAV095-16 furnace and a Carrier CK5BXA042000ABAA A/C unit installed in 2000 which replaced a unit of the same size.
House was built in 1965
Moved into the house in 1998
Mildew in bathroom cabinets and den cabinets when I moved in.
Rest of house fine and humidity levels fine until 2003
Attic is vented with ridge vent, three gable end vents, soffit vents, and two passive roof vents
Crawl space is vented with 8 vents
The construction and ventilation is the same as all the other house built around here at the time. Not many places around here have a closed/unvented crawl space. Currently houses are being built with vented crawl spaces.
Things done to try to fix humidity problems:
Moved ductwork and furnace unit to attic from the crawl space and had it tested for air leakage with blower door test. The existing ductwork under the house was disconnected somewhat in places which I am sure contributed heavily to the beginning of the problem. (I had paid two different companies to check my ductwork, “repair” it, and reinsulated. Neither did anything past the first 15 feet or so. I am claustrophobic and did not check their work.)
Had gutters put on the back of the house
Had a French drain installed along full length of back of house last summer because my backyard slopes toward my house and water pooled against it until it drained. Have not been able to find anyone to check under the house to see what the condition of the dirt is at this point, but will soon hopefully. I know that it is working some though as the door to my bathroom shuts all the time instead of some of the time (i.e. no house movement due to clay swelling.)
Put new 6 mil vapor barrier under house
Sealed all under house leaks between house and crawl space, sealed all floor vent holes.
Sealed hole in bathtub drain
Installed energy efficient vinyl windows w/ LowE glass to replace single pane aluminum windows w/ storm windows
Sealed around vents from house to attic
Air handler blower motor speed has been adjusted to try and pull more humidity out.
I have been able to rule out laundry and showering as major contributors to the problem as I didn’t live in my house for almost a year due to an injury and I still had humidity problems just as bad as in the past. Also, I live by myself, so it shouldn’t be a big issue anyway. The folks next door are a family of five and don’t have any issues.
Changes in house besides those listed above:
Added 10 inches of cellulose insulation to attic.
Replaced all flooring, went from carpet throughout house to tile, wood, and laminate
Added more attic venting. Previous was two gable vents and two whirly gigs on the roof.
The humidity and temperature readings are based off of Radio Shack digital humidity and temp gauges.
If anyone can provide steps to take, tests to do, measurements to take, I would be glad to do that. If there are multiple steps or measurements to take, please list them all together because I will probably have to borrow equipment or have someone else do them due to lack of equipment or inability to access attic or crawl spaces by me (injury and claustrophobia.)
Thanks for any help you can offer!