Ross, be thankful for the warning your windows are giving you. While you can reduce the humidity with a dehumidifier, you will pay for it in energy costs, so it should be a last resort. Unless you have a huge family and someone is cooking (boiling water) all day, I would really suggest checking the crawlspace or basement. Tape down a square yard of plastic for a couple of days and see how much water you accumulate. For much more info plus input from some experts, check out the "Moisture Mold & Mitigation" and "Air Infiltration" threads on the TOH BB (www.pathfinder.com/TOH). BTW, it really helps to know in what part of the country you are located.