How Does High Humidity Affect Temperature & Air-Conditioning?

Humid air makes hot temperatures seem hotter.

Perceived Heat

Air conditioning systems counteract this phenomenon by drawing humidity out of the air to cool a home or other indoor area.

High humidity can make a hot day feel hotter as the water vapor in the air transfers the heat to people. Meteorologists measure the perceived temperature with a chart that the National Weather calls the “Heat Index.” An air temperature of 96 degrees Fahrenheit, for instance, actually feels like 121 degrees Fahrenheit when combined with a relative humidity of 65 percent.

Air Conditioning and Humidity

An air conditioning system draws humidity out of the air by pushing it past a chilled evaporator coil, according to the Consumer Energy Center. The dried, cooled air blows through ducts to cool a home or building. The Weather Channel recommends equipping indoor spaces with one ton of air-conditioning equipment per 600 square feet to ensure adequate dehumidification.


The Weather Channel warns homeowners against extremes of humidity at either end of the scale. Excessive humidity can lead to mold growth, rot and dust mites, while too dry an environment can cause dry skin, static electricity and respiratory problems.