The Ideal Humidity Level for a Comfortable, Healthy Home, According to Experts

Everyone wants to be comfortable in their home, right? Besides the usual suspects (curating décor you love and adding in cozy furniture), your home’s indoor humidity contributes to this more than you might think. If there isn’t enough humidity in the air, you might notice that your throat feels scratchy or your skin seems dry. Fluctuating humidity levels can also negatively affect your home itself, warping woodwork and contributing to the growth of mold and mildew.

Fortunately, indoor air quality experts say the humidity sweet spot can be achieved with the right tools and attention to detail. Here's how.

Seasonal Guidelines for Humidity Levels  

Humidity isn’t a one-size-fits-all situation for every season. It shifts slightly depending on the weather. Generally, though, your environment's relative humidity—which, according to Richie Drew, VP of operations at One Hour Heating & Air Conditioning, is "the level of water vapor in the air expressed as a percentage of the saturation point—should be between 30 and 50 percent. “In most cases," says Drew, "this is optimal for health and sensitive home materials like wood and drywall."

Refer to the specific relative humidity levels below throughout the year:

• Winter: Maintain a relative humidity level of around 30 to 40 percent. Slightly lower levels can be good for reducing window condensation and damage to the frames due to freezing.
  
• Summer: Aim for 40 to 50 percent to limit mold growth and keep your air conditioning efficient, recommends indoor air quality expert Ken Nelson.
  
• Spring and Fall: Nelson recommends monitoring your home's humidity levels weekly so you can make small tweaks—like cracking a window on milder days—to maintain balance (30 to 50 percent) without extra energy use.

Humidity Levels Matter More Than You Think

"Keeping indoor humidity between 30 to 50 percent is more than a comfort goal," Nelson explains. "It's a scientific sweet spot endorsed by the EPA and leading indoor air quality (IAQ) experts." According to Nelson, this is the environment in which "viruses struggle to survive, mold spores stay dormant, and your skin retains enough moisture to stay comfortable."

Drew notes that staying in this EPA-endorsed range protects your house as much as your health. “Moist air can promote mold and mildew, which leads to respiratory issues and unpleasant odors,” he says. "It can also warp wood over time. On the other side, air that is too dry causes dry skin, itchy eyes, and scratchy throats. Managing humidity is about balance."

How to Measure and Adjust Humidity Levels 

To measure your humidity levels, Drew recommends purchasing a hygrometer. "Low-tech digital models generally work well and can be purchased at most hardware stores for under $20," Drew explains. "Some thermostats have that feature built in, so you can track it right from the wall control."

Once you’ve measured your humidity levels, you’ll be able to tell if your air needs adjustment. Here are a few tips and tricks for remedying dry or damp air.

If Levels Are Under 30%—Too Dry

It’s likely a colder month where everything feels dry: your skin, your throat, and the air. Here are the top things you should do to bump up the humidity, says Drew.

• Use a humidifier
• Lower your thermostat slightly
• Air dry laundry inside
• Place bowls of water near heat sources
• Avoid running exhaust fans more than needed

If Levels Are Over 50%—Too Damp

Summertime brings moisture and damp air. These tips from Drew help take some of the moisture out of the air.

• Use a dehumidifier in damp areas
• Make sure your AC’s filter is clean and the unit works properly
• Fix plumbing leaks quickly
• Run the exhaust fans in the bathroom and kitchen 
• Open your windows to increase ventilation 
• Seal and insulate your doors, windows, and attic