Home Humidity and Your Asthma

Home humidity problems are not only annoying and uncomfortable but can also lead to problems with your asthma control. When humidity levels in the home are high, dust mites and molds tend to thrive. These can trigger asthma symptoms such as:

How to Know If Your House Humidity Is Too High

You can look around your house for a number of indicators of high humidity levels such as:

  • Condensation on the inside of windows
  • Damp spots or water stains on ceilings or walls
  • Water collecting where it doesn’t belong
  • Mold growth or mildew
  • Moldy or musty smell
  • Peeling paint
  • Sweating on the basement floor or walls
  • Condensation on water pipes
  • Lingering odors
  • Decaying wood

Also look for signs of allergies in anyone living in the home, such as worsening post nasal drip or hay fever sneezing. Even in the absence of any of of the indicators listed above, this may hint at a problem.

Woman using an electric fan.
BURGER / Getty Images

10 Tips to Decrease House Humidity

Much of the humidity in the house results from our own lifestyle habits. There are a number of things we can do to decrease humidity in the house:

  • Use exhaust fans: Placing exhaust fans in the kitchen and bathroom can decrease house humidity. Doing so keeps the moist air from escaping into other areas of the home and decreases humidity levels at the source. Other areas where exhaust fans may help include attic and crawl spaces.
  • Open windows: Many of our homes are now built to be airtight to save on energy. While this may save money on energy bills, an airtight home can trap air pollutants. Occasionally opening windows can allow these pollutants to escape the home. Of course, this needs to be counterbalanced by the air quality in your community. If pollen levels are bad, or you live in a big city with poor air quality, you may not want to do this. You may also want to consider using air conditioning. Air conditioning filters help keep out pollens and other spores as well as decreasing relative humidity, which will lower levels of dust mites and mold. Just make sure water isn’t pooling in the air conditioner.
  • Decreasing showering/bath time: Long, hot showers or baths add to indoor humidity. Be sure to leave the bathroom exhaust fan (if you have one) on for long enough afterward to get rid of excess moisture.
  • Hanging wet clothes outdoors: If you don’t have a clothes dryer, drying clothes indoors can result in aerosolization of lint, fabric softeners, and detergents that can trigger an asthma attack.
  • Vent clothes dryer to outside: Some people do not vent clothes dryers to the outdoors to save on heating costs. Not only can this increase home humidity, but it also may increase indoor air pollution, which can worsen asthma symptoms.
  • Washing only full loads of laundry: You use the same amount of water no matter how much you have to wash. Making sure each load is full will decrease the total number of loads done and can help with home humidity.
  • Houseplants: Indoor houseplants release moisture into the air. Consider putting houseplants outside temporarily or concentrating them to one or a couple of rooms in the house. Be careful not to overwater.
  • Firewood: Keep firewood outside as it retains a significant amount of moisture.
  • Gutters: Make sure that downspouts and gutters are clean and are moving water far enough away from your home. If water is pooling near your home walls and seeks into the foundation humidity can rise. Additionally, make sure not to overwater your outdoor plants as this can also lead to rising home humidity levels.
  • Lower indoor temperature: Relative humidity is proportional to air temperature. Colder air holds less moisture and is drier. Running your AC, while increasing costs, can lower your home humidity.
  • Dehumidifiers: If these tips do not decrease your home humidity problems, you might consider a dehumidifier. Winter and summer bring different humidity challenges and you may need to consider the pluses and minuses of either a whole-house humidification system or a portable humidifier. This can be really helpful if you have a moist or humid basement.

Doctors used to recommend that patients with asthma move to warm dry climates that you find in places like in the southwest, but air conditioning and dehumidifiers have largely made these recommendations a thing of the past. You can now control your microenvironment in the home at a relatively low cost. However, be careful now to make the air too dry.

While air that is too humid can lead to increases in dust mites and other triggers, very dry air can trigger a cough in asthmatics. Drying out the mucous membranes of your respiratory system may place you at increased risk for respiratory infections. Dry mucous membranes also may aggravate allergy symptoms and make your asthma symptoms worse.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Global Initiative for Asthma. Global strategy for asthma management and prevention, 2022.

  2. Environmental Protection Agency. A brief guide to mold, moisture and your home.

  3. Won HK, Kang SY, Kang Y, et al. Cough-related laryngeal sensations and triggers in adults with chronic cough: symptom profile and impact. Allergy Asthma Immunol Res. 2019;11(5):622-631. doi:10.4168/aair.2019.11.5.622

  4. D'Amato M, Molino A, Calabrese G, Cecchi L, Annesi-Maesano I, D'Amato G. The impact of cold on the respiratory tract and its consequences to respiratory health. Clin Transl Allergy. 2018;8:20. doi:10.1186/s13601-018-0208-9

By Pat Bass, MD
Dr. Bass is a board-certified internist, pediatrician, and a Fellow of the American Academy of Pediatrics and the American College of Physicians.