Humidity can be tough on your air conditioning unit and send your energy bills rocketing. This is primarily because of its dual seasonal nature – your AC unit needs to reject humidity in summer (when it’s available in plenty), and is in dire need of it during winter (when its scarce). Add to this the fact that the absence/presence of humidity is also the prime catalyst for significantly reducing your energy bills.

To better understand why humidity is crucial to the proper functioning of your air conditioning unit as well as to decreasing your energy costs, it is essential to understand humidity itself followed by the tasks an AC unit performs.

How Humidity Affects Cooling

Humidity is the label given to all moisture present in air. Every AC comes equipped with a cooling coil attached to a compressor. Air flowing through the ducts continuously collides with the coils and reduces the heat coming from the outside. The result is a cooler and more comfortable room temperature. Humid air contains high amounts of vaporized liquid (moisture). It’s harder to cool liquid. When the moist air collides with the cooling coils, the moisture starts condensing. That’s one way the air conditioner dehumidifies the air – by condensing the moisture out of it.

This causes most of the energy supplied to the coils to be used for removing humidity instead of cooling the room. Only when the humidity levels have reached acceptable levels does the coil starts cooling the air. High levels of humidity cause the AC to utilize more energy for its compressor. As a result, not only does it increase energy costs, it also decreases the effectiveness of the unit as well as the comfort levels for the occupants.

How Humidity Affects Heating

During winter, the atmospheric moisture levels can drop. As a result, the heat pump in the unit will have to work a lot harder. This is primarily because it is a lot easier to transfer heat through convection then radiation. Moist, humid air significantly increases the transfer of heat energy via convection currents and hence brings the temperature of the room to expected, comfortable levels.


Air conditioning units can be paired with humidifiers and de-humidifiers to control the moisture levels in the air that is being channeled through the ducts. Proper humidity levels will not only increase the effectiveness and lifespan of the air conditioning unit, it will also significantly decrease its energy consumption – and hence the bills.

This article was provided by American AC Heat Plumbing. Since 1981, American Air has been providing professional air conditioning and heating service and repair. Check out their $99 tune-up special – good for your air conditioner or furnace!


James Smith

As you can tell from our humble beginnings in 1981, we began as a family-owned business and stayed a locally owned air conditioning and heating company in Los Angeles county for nearly 40 years.