Indoor Humidity and Dry Air: The Effects on Your Home's Comfort Level


Goldilocks reminds us that too hot or too cold is not “just right.” This is especially true when it comes to indoor comfort. But there is more to that “just right” indoor feeling than the temperature set on your thermostat. Indoor humidity control is an essential part of creating your ideal comfort in your home.

Indoor Humidity 


Too high or too low humidity can certainly put a damper on indoor comfort. In fact, the idea of indoor humidity control sparked one of the first uses of air conditioning in the southern U.S.

In the early 1900s, Stuart W. Cramer installed his first air conditioning system at his cotton mill in North Carolina to create the “ideal” humidity level for his textiles. However, conventional air conditioners (and heat pumps) are not meant to control indoor temperature and humidity independently.1 Dehumidification just happens to be an incidental by-product of the refrigeration cycle!

The main job of an air conditioner is to cool your indoor air. However, an air conditioner’s process of cooling the indoor air also may help lower the indoor humidity level. When it comes to indoor humidity, the Department of Energy suggests that an air conditioner may make an indoor space more comfortable in hot, humid climates. But if the indoor humidity level is still too high, you may feel uncomfortably damp despite a cooler temperature in your home.2

Your indoor comfort level is impacted by the relative humidity inside your home. Relative humidity is the percentage of water vapor in the air, compared to how much the air can hold without dropping out at a specific temperature.3

The Indoor “Feel Likes” Temperature


Your indoor “feels like” temperature has a lot to do with how much moisture, or water vapor, is in the air in your home. Too much water vapor in your indoor air may make your home feel humid, while too little moisture can make your home feel dry. 

Humidity may impact your “feels like” temperature because it affects evaporation rates. When the air is saturated with water vapor, sweat may not evaporate from our skin as quickly as it would at a lower humidity level. This phenomenon may make us “feel” warmer than the actual temperature reading because evaporation is slowed.

When the indoor humidity is low, it can allow the moisture on your skin to evaporate at a greater rate.4 If you want to stay cool during the warm months, this can be a good thing.  But if it’s already cool in your house, rapid evaporation can make you “feel” colder than the temperature on the thermostat. That’s because when moisture evaporates from our skin, it has a cooling effect. But if the indoor air is too dry, additional evaporation may leave our skin and other body parts that require moisture, feeling dry and parched.5 Proper humidity levels keep you, your furniture and your home from drying out.    

A study shows that most people will feel cooler in a room at 75°F with a relative humidity level between 50% and 55% than in a 75°F room with a higher relative humidity level.6 

HVAC Sizing Impacts Indoor Humidity


When you need cool indoor air, you might think that over sized air conditioners (or heat pumps) would be great to have.  However, an over sized unit may create bursts of cold air, tricking your thermostat into shutting off the system before the entire house reaches the desired temperature. This rapid “cycling” may not remove as much moisture as a properly sized and matched unit. 

A unit that is too large for your home may cool your indoor space quickly, but it could turn off before providing the incidental dehumidification that helps make you comfortable in your home. When an air conditioner is sized and installed properly by a professional HVAC technician, it will cycle on and off at various intervals to maintain the temperature setting on the thermostat and provide incidental humidity control. It is not unusual for an air conditioner to operate using long on and off cycles. In fact, this is preferred for energy-efficient performance and humidity removal. 

Indoor Moisture Control


Depending on the season and the geographical location of your home, your indoor spaces may be prone to high humidity levels. If your humidity is high and the indoor air quality becomes an issue in your home, a licensed professional HVAC dealer may suggest a separate solution. A whole-home dehumidifier may be what you need to reduce the relative humidity in your home to a comfortable level.

A whole-home dehumidifier is designed to:

  • Reduce the cold, clammy feeling that comes from lowering the temperature on your thermostat in order to reduce the humidity level in your home7
  • Help create an environment where dust mites can’t easily survive (when the air is maintained below 50% relative humidity*)7
  • Helps protect your hardwood flooring from warping when set to maintain the relative humidity in the range recommended by the hardwood flooring manufacturer7

But despite site-specific variables, every person has unique temperature and humidity level preferences to get that “just right” feeling. If you feel the moisture level is too high for your indoor spaces, your licensed or professional HVAC dealer can inspect your system and provide dehumidification solutions that can create that “just right” feeling in your home.


1 American Society of Heating and Air-Conditioning Engineers. Top Ten Things About Air Conditioning. n.d. 4 May 2017.
2 Department of Energy. Energy Saver - Dehumidifying Heat Pipes. n.d. 2017 4 May.
3 The University of Illinois Extension. Treehouse Weather Kids. n.d. 4 2017 May.
4, 6 Dougherty, Elizabeth. MIT School of Engineering. 10 May 2011. 2017 4 May.
5 Energy Star. Common Home Problems and Solutions: Dry Air. n.d. 2017 4 May.
7 Clean Comfort Indoor Air Essentials. Dehumidifiers. n.d. 4 May 2017.