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Serving Northern California Since 1946

Serving Northern California Since 1946


DeHart Plumbing, Heating, and Air Inc. Blog

Some Facts About Humidity and Cooling Your Home in Summer


When it’s hot in your home during a summer day, what do you do? If running ceiling fans and opening windows for a breeze isn’t enough—and in Modesto, it often isn’t—then you probably turn on your central air conditioning system. This can often do the job. But what about on days when the humidity is high? Does the air conditioning help overcome the humidity?

The answer is: probably not.

Humidity is a big problem during the summer when it comes to comfort—and it can also cause water damage to your home and help the growth of mold and mildew. We want to share a few important facts about humidity and how you cool your home.

The Central Air Conditioner Is Not a Dehumidifier

You may have heard that running an air conditioner can dry out the air in your home, making it too dry. There is some truth to this, especially on already dry days. When your central air conditioner is running, it draws some moisture out of the air that moves over its evaporator coil. The evaporator coil draws thermal energy from the air through evaporation, and if you remember from high school science, evaporation also causes moisture to condense on the surface. You see this all the time on the outside of glasses with cold beverages. As the refrigerant absorbs heat, it also pulls moisture from the air that condenses along the coil, which then drips down into a pan and out of the AC.

However, this is a dehumidification property of the AC. It is not a dehumidifier. When the relative humidity in a home rises above 60%, there’s little an air conditioner can do to change the levels to more comfortable ones.

Cooling Power Alone Doesn’t Overcome Humidity

Okay, so the AC doesn’t dehumidify. But it still keeps you cool, and that overcomes humidity, doesn’t it?

No, it doesn’t. It helps you feel cooler in general because it lowers air temperature, but the humidity makes it harder to do the job. Moisture levels in the air don’t change the air temperature—instead, they trap heat inside your body so the air temperature feels hotter. When humidity makes the air feel 8° warmer, you’ll have to run the AC for longer and longer to make up that extra feeling of heat. This means plenty of energy waste and an air conditioner that runs down early for so much additional labor.

The Whole-House Dehumidifier Is the Solution

Combating humidity requires a special installation: a dedicated whole-house dehumidifier. You can look to our indoor air quality experts in Modesto, CA to equip your HVAC system with a dehumidifier. You’ll be able to change humidity levels for the ideal balance through your thermostat, and the dehumidifier will not interfere with the regular operation of the air conditioner. Not only will you enjoy better comfort during humid days, but you’ll also avoid other troubles from humidity such as water damage and harmful mold growth.

To find out more about dehumidifiers and other options for indoor air quality, call our professionals today.

Greenhart can make your home a breath of fresh air. Live Green, Save Green!

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