Why Humidity Matters for Air Conditioning

humidity and air conditioningHumidity or the level of moisture in the air plays an important role in indoor comfort. Humidity removal is accomplished with a properly designed and installed air conditioning system. When your cooling system is operating, it is not only cooling air, but it is also removing moisture. When your system is sized correctly and running well, it will do the best job of removing moisture from the air and keeping you more comfortable.

How Air Conditioners Help Control Humidity

Your comfort level is determined by a combination of temperature and humidity. Lower humidity makes it easier for perspiration to evaporate from your skin. So instead of visibly sweating, you just feel cooler as the water droplets evaporate. When the humidity is higher, your body can’t effectively cool down through perspiration, so that makes your home uncomfortable, even if the temperature isn’t that high.

The first air conditioners were invented as humidity control devices. Today’s modern air conditioners remove humidity from the air and cool your home in an updated way. When the AC Unit turns on, warm air from the house blows across the evaporator coil in your air handler. As this air is rapidly cooled, it causes moisture in the air to condense and be collected by your indoor unit. This is why there are drain pipes to handle condensation from the system running which either allows the water to drip outside or into a drain in your home’s plumbing.

How AC Size Matters in Humidity Control

A properly sized AC Unit will balance the ability to push a large volume of cold air into your home with the need to remove humidity. Too large a system (in tonnage) and the AC will kick on, drop the temperature down and kick off in short cycles, which are not effective at removing much humidity from the air. Too small a system simply won’t be able to keep up with the cooling needs of the home, so even though the air might be dry, the temperature alone will make you uncomfortable. (Think about heat in Arizona, where there is rarely a humidity problem, but it can still get pretty uncomfortable outside). When balanced properly, the AC unit will both cool and remove humidity effectively, providing you with the best possible comfort.

Ways to Help Control Humidity

  • Don’t use the “Fan” setting on your system. Allow the fan to kick on and off automatically when the system is running. Allowing the fan to run constantly may keep humidity in the home and reduce the effectiveness of your air conditioner.
  • Don’t open all the windows when it is very humid out. If the air outside is cool, this might seem like a good idea to save on cooling costs. However, when it is very humid outside, this just brings that humidity into the house and makes the air conditioner have to work harder to dehumidify the next time it runs.
  • Use exhaust fans for cooking and in bathrooms to remove steam from the air.
  • Although full basements are uncommon in the Charlotte, NC area, there may be some homes that can benefit from a seperate dehumidifier to help control moisture in the air.


Need help figuring out if humidity is the reason for your comfort problems? Contact us for a free comfort evaluation.