How to Achieve Ideal Home Humidity Levels

Humid air and damp surfaces in your home can lead to bad odors, mold and mildew, or even damage to paint, wallpaper or furniture. On the other end of the spectrum, overly dry air — a common side effect of a gas or electric furnace — can irritate your respiratory system. That’s why it’s important to monitor humidity year-round and take steps to control it.

Overly damp air can happen in any weather. Moisture condenses into water droplets when warm, humid air contacts a cool surface, such as uninsulated cold-water pipes. Cooking, bathing, drying clothes, washing dishes and several other everyday activities also release moisture into the air. This can make your home uncomfortable, particularly in the summer. In the winter, certain heating appliances, including unvented natural gas space heaters or kerosene heaters, can also increase the moisture inside your home. Plus, any cool surfaces such as windows, walls and doors that lack proper insulation can gather condensation.

When you see moisture accumulating, dry it promptly and deal with the source of the problem. Your best bet for controlling moisture buildup is minimizing cool surfaces and reducing humidity.

Storm doors and windows minimize cool surfaces in the winter by separating the interior from the cold, outside air. Double- and triple-pane windows also insulate interior glass from the cold. These improvements will not only reduce moisture, but they’ll also make your home more energy efficient year-round. Pay attention to window treatments as well. Opening drapes and blinds in the winter allows warmth to reach the interior glass. Some condensation may occur, but the improved circulation makes it less likely to accumulate.

Adding insulation to cold-water pipes eliminates a common cool surface in warm weather. Straight and angled sleeves let you fit insulation to your pipes; just slide on the sleeves and seal the slits and joints with duct tape.

Another humidity controller is your heating and cooling system itself. Gas and electric furnaces reduce humidity with dry heat. Air conditioning lowers the moisture level as the air cools. Keep registers open and unblocked to allow for good airflow, and have the systems inspected and serviced regularly to make sure they’re functioning properly.

Caulking and weatherstripping improve energy efficiency and prevent humid air from entering a home. They also reduce the air exchange that allows moisture to move out of the house. Bathroom exhaust fans, dryer exhausts and ducted kitchen exhaust hoods that vent to the outside will remove moisture created by showering, bathing, drying clothes, washing dishes and cooking. Keep these devices free of dust, lint, grease and anything else that could keep them from working efficiently.

Other simple ways to reduce air moisture include:

• Covering pots while cooking, when possible
• Leaving interior doors open to allow good air circulation
• Storing firewood outside
• Covering aquariums

If high humidity is a problem you can’t overcome by other methods, remove moisture from the air with either a whole house dehumidifier or ones for individual rooms. They’re effective in laundry rooms, basements, bathrooms and any room that isn’t air-conditioned or has poor air circulation. Look for ENERGY STAR^® certified models, which consume less energy than conventional dehumidifiers.

Moisture in the home isn’t always as obvious as water beading on a window. Knowing other places where it can accumulate can help you prevent problems.

Poor ventilation in an attic can result in condensation, promoting mold growth in the framing elements of the house. This can affect your home’s structural integrity. Keep eave vents clear of insulation and make sure you have adequate airflow. See Ventilate Your Home for ideas to improve air circulation in your house.

A sealed, unused fireplace creates an opportunity for moisture problems. If air doesn’t circulate in the fireplace, condensation can accumulate on the walls and soak into the masonry. Make sure some air can flow through the fireplace but that rain can’t enter it.

If you have a crawlspace, moisture from the soil can enter your home and increase the level of humidity. Installing a vapor barrier over the bare soil blocks the moisture, keeping it out of your living space.

Rain that seeps into your home’s foundation will also lead to moisture problems. Make sure your gutters work properly and that they direct water away from your home’s foundation. Read Gutter Cleaning and Repair for instructions on maintaining your gutters.

Q: What's a good humidity level in a house?
A: For maximum comfort, the humidity levels in your home should be somewhere between 30 to 50 percent. If the humidity is too low, it can make your skin and eyes feel dry. If the humidity is too high, it can create condensation that can grow bacteria and mold, which can lead to allergies and breathing problems.

Q: What's a good indoor humidity level in summer?
A: In the summer, it's ok for the  humidity level to be higher -- usually between 50 and 60 percent.

Q: What's the best way to control indoor moisture humidity at home?
A: To reduce the amount of moisture in the air, use air conditioners and dehumidifiers. This is especially true in hot and humid climates. For tips on selecting the best air conditioner or dehumidifier for your home, read the following:

How to Choose the Best Window Air Conditioner

Find the Best Central Air Conditioner for Your Home

Best Humidifier Buying Guide