Humidity

By Anne Fonda

Just what is humidity, and why does the humidity level in your home matter? 

Humidity is the amount of moisture in the air. Both the outdoor and indoor humidity can vary naturally depending on the weather outside. In cold temperatures, the humidity is naturally lower. In warmer temperatures, the humidity will be higher.

You can feel this as the seasons change. In the winter, your skin may dry out or your lips might chap. In the summer, high heat and humidity can make you feel sticky and uncomfortable. 

In addition to affecting your comfort, the humidity level in your home can negatively or positively affect the indoor air quality (IAQ). 

High humidity can lead to increased airborne pollutants such as mold spores, dust mites, and other allergens that thrive in a moist environment.

Low humidity can cause itchy eyes and throat, dry skin, and nasal congestion. 

While you can’t control the outdoor humidity, with the right HVAC equipment, you can achieve the ideal home humidity. But what is the best indoor humidity?

According to the Environmental Protection Agency (EPA), the best home humidity levels will range between 30-50%. Between 30-45% in winter and 40-50% in the summer should have you feeling comfortable. 

The American Society of Heating, Refrigeration, Heating, and Air Conditioning Engineers (ASHRAE) says indoor humidity above 60% is considered high indoor humidity. At this level, mold and mildew can thrive. At higher humidity levels you may also notice a musty smell or peeling paint.

If it’s summertime and your house is feeling warm and sticky, turn on your air conditioning system. Running your air conditioner or heat pump will also dehumidify your house. If it’s not warm enough outside to justify running your cooling system, you may want to consider a dehumidifier.

If the humidity is because of a flooded basement, a portable dehumidifier may be all you need to dry things out. But if high humidity is an issue in your home, installing a whole-house dehumidifier may be a good option.

Anything under 30% humidity is considered low. But humidity levels under 40% may make your home feel a little dry. Between 40-45% humidity is the sweet spot for many homes in the winter.

If you have low humidity, you may notice more static electricity, including getting zapped when you flip a light switch. Low humidity can also cause dry skin, increased risk of respiratory symptoms, and drying and cracking of wood.

We’re all about offering whole-home comfort solutions. While you could get a portable humidifier or mister for a bedroom, if you want the humidity level to be more comfortable everywhere, we recommend a whole-house humidifier for precise humidity control. These systems can be standalone or connected to your HVAC system to provide you with comfort all year long.
Looking for humidity control solutions for your home?

Contact your local American Standard dealer for expert advice and product recommendations tailored to your home.

A Content Writer with Trane Technologies, Anne Fonda researches topics and writes for Trane® and associated residential HVAC brands. She works in collaboration with Trane Technologies subject matter experts, offering easy-to-understand, informative content on complex topics. Her goal is to help consumers make informed decisions on the products and services they need. 

She has written for HVAC and other service provider websites for over 16 years. Before transitioning to web content writing, Anne had a 14-year stint as an award-winning journalist. She graduated cum laude from the University of Missouri-Columbia School of Journalism. When she’s not working, Anne enjoys playing word games, reading, gardening, spending time with family, and visiting gardens and museums.

Expert review by Jennie Bergman, Senior Product Manager, Indoor Air Quality