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  4. How to Understand and Control Home Humidity Levels
  • Learn indoor humidity basics

    Maintaining healthy humidity levels in your home can help keep mold, mildew and allergens at bay.

    Understand the basics of humidity to better prevent it from causing mold, mildew and other issues in your home.

    • We all look forward to the warm and sunny days of summer, but the muggy, humid air the season brings with it? Not so much. When that humidity comes into your home, it can bring in unwanted particles like outdoor allergens and exhaust, or encourage the growth of mold and mildew in rooms where you use lots of water.

      Luckily, there are steps you can take to treat your indoor air and better mitigate pesky particles. By taking extra precautions and monitoring the air outside, you can take control of your home’s air quality all year long.

      Learn indoor humidity basics

      Understanding the foundations of humidity can help you make the right decisions when it comes to your indoor air.

      • A little humidity is good—the U.S. Environmental Protection Agency (EPA) suggests keeping indoor relative humidity (RH) between 30% and 50%.¹
      • If the RH in your home exceeds 60%, it can encourage mold and mildew growth in rooms that tend to be damp (think: the bathroom and kitchen).¹
      • High humidity in your indoor air can worsen the symptoms of asthma.²
      • Household pests like insects and dust mites are attracted to high humidity areas.¹
      • Common household causes of high humidity are dishwashers, dryers and showers that release excess steam, leaky pipes and stovetop cooking.¹
      • Leaving windows open can let in humid air carrying allergens, such as pollen, exhaust particles and dirt.

      Aim for home humidity control and improved air quality

      The good news: you can easily get a handle on humidity before it becomes an issue. Here are some simple steps you can take to prevent humid air from causing problems in your home.

      • Keep your HVAC system up-to-date and in good condition to help ensure that you’ll have proper air circulation in your home all season long. Check the insides of your vents to make sure they’re mold-free.³
      • Replace your HVAC filter often (we recommend at least every 90 days for 1” filters; and every 12 months for 4”, 5” and 6” filters). A clean filter can help capture mold spores and other unwanted particles from the air passing through the filter that are present in humid air. If you’re using a Filtrete™ Smart Filter, keep an eye on the app for a notification when it’s time for a new one.
      • Run an exhaust fan in the kitchen when you’re cooking on the stovetop or using the dishwasher, and leave it on for a few minutes after you’ve finished. Steam hangs around in the air even after you’ve left the kitchen, and keeping the fan running helps remove even more from the room.
      • Check your bathroom and kitchen appliances and plumbing fixtures for mold. This will help you identify the areas in your home that need extra help filtering out mold- and mildew-causing particles.
      • If you want to target a specific room in your house, a Filtrete™ Air Purifier could help reduce even more particles you don’t want hanging around. You can also invest in a dehumidifier if humidity is a persistent issue in your entire home.
      • Take advantage of the warm weather—taking cooler, shorter showers is a refreshing way to cut down on steam that fills up your bathroom.
      • Clean your gutters after heavy rainfall or at the beginning of each season, and ensure downspouts are directed away from your house. Gutter debris and damage are a common culprit for indoor water leaks.³
      • Keep an eye on the outdoor air quality in your city. If it’s especially humid or there’s an air quality warning, it’s a good idea to turn on the air conditioning instead of opening a window.

      The first step to improving the quality of your indoor air is to understand the air itself. With the basics of home humidity levels, you’ll be better prepared to manage indoor humidity issues.


      1. https://www.epa.gov/mold/mold-course-chapter-2#Chapter2Lesson3

      2. https://www.cdc.gov/niosh/topics/indoorenv/mold.html

      3. https://www.epa.gov/mold/mold-course-chapter-2#Chapter2Lesson4