Here’s the Ideal Humidity Level for Your Home — And How to Control It

Everyone knows how important humidity can be for your skin, hair, and overall health, but did you also know that humidity is vital to the health of your home? If the humidity level in your house dips too low, your furniture and home will deteriorate, and certain germs will thrive. 

Ideal in-home humidity levels should hover around 45%. Anything under 30% is too dry, and over 50% is too high. So, how can you maintain a good humidity level in your house? Here’s everything you need to know, from how to assess how humid your home is, to determining whether you need more or less moisture in the air.

You mean you don’t have a sixth sense for humidity levels? Yeah, no, almost no one does. But there are some simple ways you can determine if the humidity in your home is too low or high.

• Fogging and condensation accumulating on windows, moisture, and mold occurring on walls and ceilings are indications of too much humidity.
• Increased instances of static electricity, dried and cracking millwork, and chipping paint indicate low humidity levels.

If you really want to get serious about humidity, you can get a device called a hygrometer to accurately read your home’s humidity levels. You can score a cheap one (digital or analog, whatever your style) for less than $15 online.

Or, if you really want to invest in your healthy home, spring for a more advanced device that measures temperature plus levels of humidity, carbon dioxide, toxic chemicals, and dust in your air.

During the winter, especially, humidity levels drop because cold air holds less moisture than warm air. Homes that utilize forced air heating have an exacerbated problem because furnaces use combustion to create hot air, thus burning out most of the water vapor that existed in the first place. To make matters worse, when humidity levels dip, the ambient air feels cooler than in more humid environments, and you turn up the heat to compensate.

Low humidity causes static electricity, dry skin and hair, increased susceptibility to colds and respiratory illness, and can allow viruses and germs to thrive. Wood floors, furniture, and millwork will split and crack, the paint will chip, and electronics can be damaged because of low humidity levels.

Adding a humidifier to your home will remedy these problems, and there are three standard types from which to choose.

Adding moisture to the air is as simple as placing a vessel of water on top of, or next to, a radiator or other air heating system. Leaving wet towels and clothes out to dry is another way to introduce moisture into the air. This is a very low-tech and low-power method, though. The strength and humidity controls are limited, and available moisture is dependent on the size of the vessel used and must be frequently refilled.

Try these household tricks: 5 Ways To Add Moisture to the Air Without a Humidifier

The most common type of humidifier is a portable one, like the type you set down on the floor or another surface. There are a couple of types: cool mist and warm mist (and dual), both of which use a reservoir to hold water. The cool mist uses a wick to absorb the water, and a fan blows air through a moistened filter, and as the air passes through the filter, it evaporates some of the water into the room.

Warm mist humidifiers use a heating element that heats the water before dispersing it into the air. The pros of portable systems are that they are easy to use, a variety of styles and prices are available, and you can easily move them around as needed. However, similar to the evaporative method above, control and measure of relative humidity is limited, and you have to refill the reservoir about every 24 hours.

Check out this shopping guide: 8 Stylish Humidifiers That’ll Solve All Your Winter Woes

For the best and most controllable humidity system, add a whole-house humidifier to your furnace to have vapor distributed directly into the heated air and circulated throughout the house via your normal duct system.

The whole house system is the most expensive option and requires a cold water connection and space for the humidifier unit. With a whole house humidifier, you control humidity levels with a device called a humidistat (yeah, like a thermostat) — this method has the greatest humidification capacity and provides the most consistency overall.

It is possible for homes to have too much humidity (especially in certain regions), creating its own set of problems. If your humidity levels are high, you might begin to notice condensation around your home, especially at your windows in winter: When warm, moist air inside comes in contact with cold air on the other side of the window, the temperature drops, and the air can no longer hold water vapor, resulting in condensation.

If a home does not have the proper mechanical and natural ventilation, excess water vapor from the air can travel through walls and ceilings, causing wet insulation, peeling paint, mold on walls, and rot in woodwork. Try these steps to lower humidity in your home.

• If you have a humidifier, turn it down or off.
• Use a dehumidifier, particularly in basements and during the summer.
• Use exhaust fans while cooking and bathing, or open a window if there is fresh, drier air outside.
• Reduce the amount of water introduced into the home by cooking with covered pots; taking cooler, shorter showers; venting clothes dryers directly to the outdoors; and reducing the number of plants in the home.
• In tightly constructed homes, use an energy-recovery ventilator.