Ideal Indoor Humidity Levels & How to Control Them at Home

We all know how important humidity can be to your skin, hair, and overall health, but did you also know that it’s vital to the health of your home? If humidity levels dip too low your furniture and house will deteriorate and certain germs will thrive. Let’s talk about what humidity levels you should keep in your home year round, and different techniques to do so.

Ideal in-home humidity levels should hover around 45%. Anything under 30% is too dry, over 50% is too high.

How to Gauge Indoor Humidity Levels

You mean you don’t have a sixth sense for humidity levels? Yeah, no, almost none of us do. But there are some simple ways you can determine if humidity in your home is too low or high:

  • Fogging and condensation accumulating on windows, moisture and mold occurring on walls and ceilings is an indication of too much humidity
  • Increased instances of static electricity, dried and cracking millwork and 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’s your style) for less than $10 online. Or if you really want to invest in your healthy home, a device like Awair — which measures temperature plus levels of humidity, carbon dioxide, toxic chemicals, and dust in your air. (You can plug a humidifier directly into the Awair Glow device and have it come on automatically when the humidity drops inside.)

What to Do If Humidity Levels Are Too Low

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 more humid environments, and we 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, paint will chip, and electronics can be damaged because of low humidity levels.

Adding a humidifier to your home will remedy these problems; there are three standard types from which to choose:

Natural Evaporation

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 (they make chic little containers just for this purpose). Leaving wet towels and clothes out to dry are other ways to introduce moisture into the air. This is a very low-tech and low power method, however the strength and humidity controls are limited, and available moisture is dependent on the size of the vessel used, and must be frequently refilled.

Portable/Room 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 two types: cool mist and warm mist, both of which use a a reservoir to hold water. The cool mist uses a wick to absorb the water and a fan blows air through a moistened filter 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 they can be moved as needed. However, similar to the evaporative method above, control and measure of relative humidity is limited, and the reservoir must be refilled about every 24 hours.

Whole House Humidifiers

The best and most controllable humidity system, you can add a whole house humidifier to your furnace to have vapor distributed directly into the heated air and circulated throughout the house 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.

What to Do If Humidity Levels Are Too High

It is possible for homes to have too much humidity (especially in certain regions) which will create 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, 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, and 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 outside; and reducing the number of plants in the home
  • In tightly constructed homes, use an energy recovery ventilator

Re-edited from a post originally published 1.20.2016 – TW

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