High Humidity in Home
It's been quite humid here in Wisconsin over the past month. The humidity in my house is frequently 60-80%.
I have a 2 1/2 ton central air (put in about 4 years ago) that works well to cool the house, upstairs isn't quite as cool as I would like, but reasonable. About 2600 sq ft being cooled.
I have large shade trees that help keep the house cooler, so even on warm (low 80's) days, the house is frequently in the low 70's, but the humidity will creep up into the 70%+ range.
Then I end up having to run the air to get some of the humidity out to get it more comfortable. I end up having to bring the house down to the low 60's before I get the humidity down to around 50% so it is reasonable comfortable.
The house is about 45 years old, fairly tight construction, but still has many old windows.
I've tried running a dehumidifier in the basement, but it barely makes a dent in the basements humidity and adds about $50 a month to the electric bill.
There are no water leaks in the house or the attic. Basement is poured and is sound and water tight. There are no long or frequent showers that add lots of humidity. Limited cooking in the house. Dryer vents outside.
Is there anything else that can be done to reduce the humidity or do I just have to settle for running the AC down to the low 60's if I want to get the humidity down?