Humidity control is a year-round issue for most homeowners. Whether you’re battling sticky summer air or trying to prevent winter dampness, keeping indoor humidity levels in check makes a big difference. Learn about the most common humidity problems, how they affect your home and health, and practical ways to take control.

Why High Indoor Humidity is a Problem

Humidity is the amount of moisture in the air. Ideally, you want the indoor relative humidity to stay between 30% and 50% year-round. Any higher than this, and you may face the following problems:

Mold growth: Excess humidity creates the perfect environment for mold to grow. You’ll most likely encounter mold in perpetually damp areas like basements and bathrooms. Colonies can even form in hidden places like behind the walls and in the attic. A musty odor and heightened allergy and asthma symptoms are common signs of mold.
Structural damage: High humidity in the winter causes condensation to form on windowpanes. As the moisture drips off the glass, it collects on the sill, damaging this material and potentially soaking into the wall, where it can dampen the insulation and render it useless. Exposure to prolonged humidity also causes warped wood floors and furniture, peeling paint, and stained ceilings and walls.
Comfort problems: When indoor air is too humid in the summer, it creates a cool but clammy feeling, encouraging you to crank down the temperature to get comfortable. This raises your energy bills and puts added strain on your HVAC system.
Pest infestation: High humidity attracts certain pests like dust mites, termites, and cockroaches. These unwelcome guests worsen allergies among sensitive individuals and further damage your home.

Tips for Controlling Indoor Humidity

If you’re not sure what your indoor humidity is, buy a hygrometer, a handheld device that measures humidity levels in the air. Carry the hygrometer from room to room, checking the reading as you go. If you find any trouble areas above 50% relative humidity, try these tips:

Size your air conditioner wisely: Air conditioners dehumidify as they cool. However, your unit won’t do this effectively if it’s oversized because it cools the air too quickly without removing sufficient moisture. If your AC is on its last leg, work with an HVAC contractor to properly size a replacement unit for your home.
Install a dehumidifier: A whole-house dehumidifier is one of the best tools for keeping humidity in check. These devices efficiently pull moisture from the air, making your home more comfortable and protecting it from damage. This solution is ideal for homes in humid climates or with oversized air conditioners. You can also place portable dehumidifiers in problem areas like the basement or bathroom.
Improve ventilation: Proper ventilation prevents moist air from lingering inside your home. Run the exhaust fan in the kitchen, bathroom, and laundry room during high-moisture activities like cooking, showering, and drying clothes to expel humid air. You can also increase ventilation on dry days by simply opening a window.
Install a vapor barrier in the crawl space: Crawl spaces often have areas of exposed earth, raising the indoor humidity level and inviting mold growth. A vapor barrier covers the ground to block moisture from seeping into your home. Pair this with proper ventilation or crawl space encapsulation for the best results.
Fix leaks and seal gaps: Water leaks are a major source of indoor humidity. A dripping pipe, leaky roof, or poorly sealed windows and doors can raise indoor moisture levels. To stop these problems at the source, regularly inspect your pipes, roof, and window seals for leaks and fix any you find. Also, add weatherstripping to windows and doors to prevent outdoor air from bringing additional moisture inside.
Maintain gutters and downspouts: Improper drainage allows water to pool near your home’s foundation, seep into the basement, and increase humidity levels. To prevent this, clean your gutters twice a year or as needed to remove debris. Then, extend the downspouts so they direct water at least six feet from the foundation.
Dry laundry outside: Drying clothes indoors adds moisture to the air, especially in enclosed spaces. When hanging laundry, do so outdoors if weather permits. If drying indoors is the only option, choose a ventilated area to prevent humidity from accumulating. As for the clothes dryer, make sure it’s properly vented outside, not into the attic, garage, or basement.

Service Experts Can Help

At Service Experts, we strive to make home comfort easy. Our ACE-certified technicians deliver fast, long-lasting solutions to indoor humidity problems. We’re here to help with services like air conditioner sizing, dehumidifier installation, and crawl space encapsulation. Comfort is more than our job—it’s our mission. Contact a Service Experts center near you today so we can make a meaningful difference in your home.