Humidity is water vapor in the air. Without it, our homes would be unhealthy and uncomfortable. Think dry, itchy skin, chapped lips, and splits forming in your wood furniture. But excess humidity is also unhealthy and uncomfortable, and tends to be a more common problem, owing to the fact that many of our favorite daily activities (cooking, showering, breathing) generate water vapor. High humidity in your home can lead to a number of problems: from mold and mildew growth to wood rot and other moisture-related, structural issues. A good humidifier can help to keep indoor humidity at safe and comfortable levels.

Do You Have a Humidity Problem?

Humidity is expressed as a percentage of the total amount of water vapor the air can hold at its current temperature. A digital hygrometer is an inexpensive tool for finding this number. Generally, indoor humidity should be kept below 60%, though for optimal comfort and health somewhere in the range of 30-50% is ideal. Condensation on windows, water pipes, and toilet tanks; musty, mildew smells, and the appearance of mold on walls or furniture, are likely signs of an indoor humidity problem.

Allergies & High Humidity

High humidity causes the proliferation of two common indoor allergens: dust mites and molds. Dust mites are microscopic critters who feed on the dust in our homes and thrive at humidity levels above 50%. People who are allergic to dust mites may experience respiratory symptoms or develop asthma. Indoor molds can also trigger allergic symptoms and lead to respiratory irritation. Additionally, mold growth can cause expensive property damage and unpleasant odors.

Lowering Indoor Humidity

Simple habits like using exhaust fans when bathing or cooking, venting clothes dryers to the exterior, and keeping the house a few degrees warmer on cold nights can decrease indoor humidity. However, if that is still not enough, a portable dehumidifier may be necessary to bring indoor humidity to comfortable levels. An air conditioner can also act as a dehumidifier, but their effectiveness varies and it won’t help you much during the cold months.

How Dehumidifiers Work

Most dehumidifiers use electricity to power a compressor, pressurizing refrigerant in coils (similar to a refrigerator or air conditioner). Water condenses on the coils and drips into a pan. Just like a refrigerator or air conditioner, they can be expensive to operate. To keep your monthly bill within reason, be judicious about how you use it. You can set a timer to operate it at night, when electricity is less expensive.

Portable vs. Whole House

If a portable dehumidifier isn’t large enough to meet your needs, or you don’t enjoy its soothing hum, a permanent whole house dehumidifier can be installed in the attic or crawlspace or added to your home’s HVAC system. You can expect to pay thousands rather than hundreds for this upgrade, but the advantages of a whole house dehumidifier may make it worthwhile. These larger units are more energy efficient, so they may be more cost effective in the long run if you use a dehumidifier regularly. And you can truly set it and forget it – there is virtually no noise, and no water tank to empty every day.

Safe and smart | Home safety


about Rebecca

Rebecca is a freelance copywriter and editor living in the SF Bay Area with her husband and two kids. She enjoys productively channeling her anxiety into safety-minded articles for home and garden, running with her robot trainer, and advocating on behalf of the Oxford comma.