Feeling Muggy Indoors

Q: My house feels uncomfortably humid. Would a stand-alone dehumidifier be a good way to fix this problem?

A: A stand-alone dehumidifier may solve the problem temporarily, but figuring out the source of the problem will lead to a long-term solution and save you the hassle of emptying a drain pan.

First, focus on low- and no-cost efforts to control indoor humidity. The following list is long, but don’t worry, these are things you can do or check by yourself.

  • Are exterior doors and windows, including storm windows, closed and latched?
  • Are the dryer lint trap and exhaust pipe clean? Does the dryer exhaust pipe go all the way outside? Try to get a hold of a shop vacuum and suck out lint that has accumulated in the pipe. Clogged dryers will make a house muggy quickly. Avoid line-drying laundry inside the house, too.
  • Do your family members use exhaust fans when bathing or cooking and turn the fans off when they are done? Do the fans actually pull air? The kitchen fan should hold up one sheet of letter-size paper when running. The bathroom fan should hold up two 2-ply sheets of toilet paper on top of each other when running.
  • When the air conditioner is on, do you feel air coming out of every vent? If not, there may be a disconnection dumping cooled air into your attic or crawl space and allowing outside air into the home.
  • Is your HVAC ductwork properly sealed? You don’t want outside air getting into ductwork through any hole. Many small holes add up to many leaks. While you are here, is it time to change your air filter?
  • If you have a crawl space, is there plastic sheeting covering the soil? A 6-mil polyethylene cover overlapping the seams by 12 inches works well.
  • Are there other places where outside air could enter your home? Focus on holes in the ceiling and floor. Is the attic door weatherstripped?
  • Are there other places where moisture is accumulating in or around your home? Have you considered roof leaks, plumbing leaks, or clogged gutters or downspouts? Do you have an excessive number of plants or aquariums in your house? Combustion appliances such as gas fireplaces and cooktops also emit water vapor that should be vented from your home.

You don’t need to give up your aquarium or gas cooktop to improve humidity, but it is important to be aware of sources and take control of the situation.

If your home is still muggy, don’t run to the store for a dehumidifier yet. Have you ever worried about the water dripping from your air conditioner’s drain line on a hot summer day? That water is a sign that your air conditioner is doing its job of removing humidity from your home. If no water is dripping from the drain line, it may mean that the line is blocked due to grass clippings, soil or mulch, which can cause humid air to be recycled back into the house. That’s not the kind of recycling we want.