How to Reduce Humidity in Your House This Summer

High summer humidity makes it difficult to get comfortable in our own homes. The air feels sticky and stifling, and prolonged bouts of high humidity can adversely affect our health and slowly degrade our homes and furnishings. Fortunately, there are several simple and affordable strategies to effectively reduce indoor humidity levels.

What High Indoor Humidity Does to Your Home and Your Health

Minor spikes in humidity aren’t especially concerning, but prolonged exposure to high humidity can negatively affect your home and health in several ways.

• Mold and mildew. High humidity provides the conditions for mold and mildew to thrive. Bathrooms and basements are particularly vulnerable, but mold has the potential to spread to the kitchen, living spaces, bedrooms, and even HVAC ducts. Unless the initial growth and humid conditions are eliminated, the mold will stain your walls and ceilings, degrade your air quality, and damage the wood and drywall in your home.
• Damaged paint, wallpaper, and drywall. Excess moisture in the air can become trapped behind paint, causing bubbling, peeling, or discoloration. It can also weaken wallpaper adhesive, resulting in curling wallpaper at the seams and edges. Over time, humidity can even degrade drywall as the gypsum and paper absorb moisture.
• Warped wood and jammed windows and doors. Wood absorbs moisture from the air, expanding in the process. If this absorption is uneven, the wood will also warp. In a home with wooden door and window frames, this translates to windows and doors that stick or jam.
• Increased allergens and worse air quality. High humidity in house HVAC systems can increase counts of mold spores and dust mites, both common allergens and sources of respiratory irritation. Heavy, moisture-laden air is also more likely to hold pollen, smoke, particulate matter, and other fine air pollution. Depending on the severity and your personal sensitivity, these pollutants could make your home feel stuffy, or they could irritate your eyes, nose, and throat.
• Physical discomfort. High humidity is uncomfortable. Our bodies keep cool via the evaporation of sweat, which is inhibited when the air is already saturated with moisture. It’s harder to keep cool in humid weather, so a humid 75°F day feels more uncomfortable than a dry 80°F day. Indoors, the discomfort is compounded by couch cushions and bed sheets that feel damp and clammy.

What Humidity Level Should Your Home Actually Be At

The EPA and HVAC professionals recommend a target relative humidity range of 30% to 50%. It’s natural for the precise figure to drift depending on the weather and season. It will be easier to keep to the low end of the range in winter since the cold winter air is naturally drier. In the summer, aim for the upper end, and don’t worry about occasionally exceeding 50% on especially humid days. You just want to make sure your indoor humidity levels aren’t routinely above 60% to avoid the worst of the humidity’s effects.

You can measure your home’s indoor humidity levels with a hygrometer, an inexpensive tool you can find at your local hardware store or online. Modern hygrometers typically indicate the temperature and relative humidity on a digital display, and they can be placed anywhere in the home. To measure your home’s humidity levels most effectively, follow these guidelines:

• Set the hygrometer away from direct sunlight, vents, doors, and open windows.
• If possible, set up multiple hygrometers in different parts of the house.
• Keep a log of temperature and relative humidity readings to track fluctuations and patterns.

How to Reduce Humidity in Your House Without a Dehumidifier

A dehumidifier is one of the most effective means of home humidity control, but there are other ways to keep indoor humidity in check. Here’s how to dehumidify a room without a dehumidifier.

• Seal and weatherproof your home. Sealing gaps and applying weatherstripping to doors and windows are common recommendations to make your home more energy efficient in the winter, but these strategies can be used in the summer to keep cool, dry air inside and hot, humid air out.
• Use your exhaust fans when showering and cooking. The steam produced while showering and cooking increases home humidity levels. Run your bathroom and kitchen exhaust fans to vent away moisture, but make sure the fans vent outside the home and not into an attic or other indoor space.
• Run your air conditioning. Using the AC is an excellent way to reduce humidity in house living spaces. The mechanism by which it cools a room naturally takes moisture out of the air.
• Use fans and promote ventilation. Fans can’t remove moisture from the air, but they can circulate the air so that humidity is more evenly dispersed. If one part of your home is prone to higher humidity, you can circulate the air to equalize humidity levels and avoid stagnant pockets that can promote mold and mildew.
• Use windows strategically. When relative humidity outside is high, keep your windows closed to avoid letting that humid air in the house. When the weather turns and you get a drier day, you can open the windows if the relative humidity is equal to or less than your indoor levels.
• Set out materials that absorb moisture. Calcium chloride, charcoal, and silica naturally absorb moisture from the air. A container of such material can be useful in closets, crawlspaces, and other locations with poor air circulation.
• Dry wet clothes outside. If you hang dry your wet laundry, consider leaving it outside instead of in the laundry room. When you hang saturated clothes inside, all of that water evaporates into the air inside your home.

When to Use a Dehumidifier and Which Type to Choose

If you can’t bring your indoor humidity levels down to 50% or 55% with some combination of the strategies outlined above, then a dehumidifier may be your only recourse. There are two main types to consider: portable and whole-home dehumidifiers.

Portable humidifiers are the simpler option. They are compact, inexpensive, and easy to set up and move about. If you’re concerned about high humidity in just one part of the home, such as the basement or a bathroom, a portable dehumidifier is the right choice. But be aware that you need to manually empty a portable dehumidifier’s reservoir as it fills up, and these appliances cannot meaningfully reduce the humidity levels in an entire home. For that you need multiple portable dehumidifiers or a whole-home dehumidifier.

A whole-home dehumidifier is integrated into the home’s HVAC system and uses the existing ductwork to dehumidify the entire home. Compared to a portable unit, it’s quieter and more energy efficient, and you don’t need to check on it every day to empty a reservoir. But the upfront cost of anywhere from $1,500 to $4,000 is much higher, and you need to include service checkups in your HVAC maintenance budget.

How Your AC Affects Indoor Humidity and When It Is Not Enough

Air conditioners don’t generate cold air. They actually pull warm, humid air from the room, and this air then passes over evaporator coils filled with refrigerant. The heat that the coils absorb is pumped outside, and the moisture in the air condenses and drips into a drain line. The now cooler, drier air is blown back into the room.

This process will naturally dehumidify a room, though the size of the AC relative to the space it is cooling is important. If the AC is too big, it will cool the room too quickly and shut off before enough moisture has condensed on the coils, leaving the room still humid and clammy. If the AC is too small, it will run constantly and never get the temperature and relative humidity where you’d like them to be.

Your AC may not be enough to adequately dehumidify a room if you live in an especially humid climate. Also, common air conditioner problems that reduce efficiency could impair your system’s ability to remove moisture from the air. Dusty evaporator coils or a refrigerant leak, for example, will keep the AC from reaching its dehumidifying potential.