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. High home humidity levels can lead to asthma symptoms such as:

High home humidity levels are a trigger that indicates too much moisture. You can look around your house for a number of indicators of high humidity levels such as:

  • Damp spots on ceilings or walls
  • Mold growth
  • Peeling paint
  • Sweating on the basement floor or walls
  • Condensation on water pipes
  • Lingering odors
  • Decaying wood
Woman using an electric fan.
BURGER / Getty Images

Humidity and Cold Air

Humidity and cold air can be a problem when they occur together. Because both humidity (putting a child in the bathroom and turning on the hot shower) and cold air improve the symptoms of croup, many parents have also thought the practices may also be good for asthma. However, both of these can be asthma triggers.

Humid air is more likely to harbor triggers such as fungus, molds, and dust mites that might worsen your asthma symptoms. When you inhale cold, dry air, it irritates and drys out the mucous membranes that line your lungs and respiratory system. This decreases the effectiveness of your body's natural defense mechanisms against viruses and bacteria. As a result, you may have an increased risk of a respiratory infection that can worsen your asthma. Similarly, this can worsen allergy symptoms that are another common trigger for asthma (a large percent of asthmatics also have allergy problems).

How to Know If Your House Humidity Is Too High

There are a number of things you can look for such as:

  • Fog on indoor windows
  • Moldy or dusty smell
  • Damp spots in the house
  • Any collection of water or mildew
  • Wet spots or water stains on ceilings
  • Look for signs of allergies in anyone living in the home such as worsening post nasal drip or hay fever sneezing

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.
  • Decreasing showering/ bath time: Long, hot showers increase humidity. Additionally, hanging wet clothes to dry indoors can result in aerosolization of lint, fabric softeners, and detergents that could lead to an asthma attack when inhaled.
  • Vent clothes dryer to outside: Some homes do not vent clothes dryers to the exterior of a home to save on heating costs. Not only could this increase home humidity, but it also may increase air pollution in the home that could worsen asthma symptoms. Also, if you do not have attic fans this can help remove moisture as well.
  • 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 house plants 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 unit, 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.

While doctors used to recommend that patients move to warm dry climates that you find in places like Arizona and New Mexico, 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, you do not want to make the air too dry.

While too humid air can lead to increases in dust mites and other triggers, a relative humidity of less than 15% can lead to a significant cough for asthmatics. Drying out the mucous membranes of your respiratory system may place you at increased risk for infections from viruses and bacteria due to decreasing natural defenses from the common cold virus or influenza. Dry mucous membranes also may aggravate allergy symptoms and make your asthma symptoms worse.

Was this page helpful?
0 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.
  • Environmental Protection Agency. A Brief Guide to Mold, Moisture, and Your Home