You are here

Media Room

Is your air conditioner ruining your air quality?

Air Quality News from IQAir, the world leader in air purifiers.

Air conditioning is supposed to make indoor living more comfortable. But an air conditioner that is used or maintained improperly can turn an otherwise happy home into an Indoor Air Quality nightmare. The reason why is a four-letter word: mold.

Molds are tiny microscopic organisms found everywhere. In the presence of sufficient moisture they grow and multiply rapidly. Exposure to mold can cause allergies, infections, neurological problems and even death. So it’s important to understand that an air conditioner used improperly can set the stage for mold to grow out of control.

This can happen when the thermostat is set too low. Many homeowners believe they can reduce or eliminate mold by lowering the thermostat. In fact, setting the temperature lower than needed greatly increases the risk of mold growth.

Comfort is not about heat, it’s about humidity

There’s a popular saying, “It’s not the heat, it’s the humidity.” Those who live in an area with high humidity know exactly what this means. When it’s 80 degrees with low humidity, a person may feel very comfortable. When it’s 80 degrees with high humidity, that same person can be miserable.

The human body cools off by perspiration. As the body perspires, the skin is cooled through sweat evaporating. But when the relative humidity in the air is high, the evaporation of sweat is greatly slowed. The temptation is to turn up the air conditioner by setting the thermostat lower. That’s a mistake – in terms of comfort and air quality.

Relative humidity and mold control

The key to mold control is to control relative humidity, which is a measurement of the amount of moisture in the air compared to what the air can hold at that particular temperature. Mold will not typically grow indoors when the relative humidity is below 55%.

Here’s the catch – the lower the thermostat setting on an air conditioner, the higher the relative humidity will be. By overcooling a home, homeowners inadvertently are creating the moist conditions in which mold thrives.

Ideal thermostat setting is about 78 degrees

Especially in hot, humid conditions, the ideal air-conditioning thermostat setting is about 78 degrees. Setting the thermostat to 78 degrees might seem high, but the key is to find the right balance.

The goal should be to maintain a comfortable environment while also taking steps to prevent mold from growing. A central air conditioning system can extract as much as nine gallons of water a day through condensation. Water collects on the coils and in the drainage. This is where mold grows if the water isn’t allowed to evaporate efficiently.

By setting the thermostat higher, homeowners will also save money on energy costs. Every degree warmer the thermostat is set saves about 10% on energy costs.

Regular maintenance is important too

Regular maintenance of an air conditioning system will help keep it running efficiently and safely and will help spot potential mold problems early. Only 42% of all homeowners with central air conditioning have annual maintenance performed, according to the U.S. Energy Information Administration. Here are a few tips on maintaining an air conditioning system:

1. Maintain the efficiency of an air conditioning system by inspecting, replacing or cleaning filters regularly.

2. Check the system’s coils and drainage regularly for any signs of standing water or mold.

3. Obtain the services of a licensed HVAC expert for a yearly maintenance check of all central air conditioning system components.

4. If mold is a problem, clean the area as soon and as thoroughly as possible. If the problem persists, consider consulting a mold remediation specialist. For more information on mold and air conditioning visit the Environmental Protection Agency website at

Click here to download a PDF of this article.

This online publication is brought to you by IQAir North America, Inc., a member of the Swiss-based IQAir Group that develops, manufactures and markets innovative air purifiers and air quality products for indoor environments around the globe. IQAir is the exclusive educational partner of the American Lung Association for the air purifier industry.

Media Contact

Public Relations Department

Joe Rookard

IQAir North America
14351 Firestone Blvd
La Mirada, CA 90638

+1 (562) 903-7600 x1115

Email Your Media Inquiry