How Do Air Conditioners With Humidistat Work?

Air conditioners with a humidistat have helped to put an end to many hot and humid days for millions of homeowners.

Air Conditioners

Air conditioners with a humidistat can be helpful.Air conditioners with a humidistat can be helpful.
By pumping cool, filtered air into a hot home, air conditioners with a humidistat relieve the common causes of mildew and mold in many climates. While a humidistat is a helpful device, it does not necessarily replace dehumidifiers in the process of dehumidifying a home.

Living in hot climates year-round often requires air conditioners. Even people who live in relatively cool places appreciate the cool, crisp feeling of a great air conditioner during the summer months. Air conditioners with humidistats offer even more than cool air; they offer dry, humidity-free air. In hot, moist climates, air conditioners with humidistats can be a godsend.


A humidistat is a controlling device used to determine the on and off cycles of an air conditioner. The humidistat automatically turns the air conditioner on when the humidity in a room or house reaches above 70 percent. A humidistat is made up of two internal electrodes that are able to sense the humidity in the air through attached sensors.


Air conditioners with humidistats vary by brand, but most function in a similar manner. According to Progressive Energy, an air conditioner with a humidistat will automatically turn on even if the room has already reached its desired temperature. The thermostat is secondary to the humidistat in this type of air conditioner. The humidistat detects humidity over 70 percent. Keeping humidity low in a home can ward off mildew, mold and other moisture-loving bacteria.


The installation of an air conditioner with a humidistat requires a professional HVAC mechanic or contractor. In order for the humidistat to work properly, it needs to be installed parallel to a home's wall thermostat. In general, the best setting for a humidistat is 70 percent. Drier areas may require a higher setting and wet areas may need a slightly lower setting. You can experiment with the setting until the air is comfortable for you.


People who plan on purchasing air conditioners with humidistats believe that their air will be consistently free of humidity. They may leave town and not realize that turning off the air conditioner (by turning off the thermostat), will also turn off the humidistat. Additionally, according to the website, using an air conditioner with a humidistat is not a replacement for using a dehumidifier. They suggest running a dehumidifier with an air conditioner. While an air conditioner with a humidistat should keep moisture down, it will not dehumidify the air, like an actual dehumidifier will.

About the Author

Ekaete Bailey began writing professionally in 2005. She has experience in journalism, copyediting, Web content, marketing, creative writing and public relations/communications, with an emphasis in travel writing. Bailey writes for a variety of print and online publications. She earned a Master of Science in public-relations management from State University of New York College at Buffalo.