Your heating, ventilation, and air conditioning (HVAC) system not only heats and cools your home but it can also keep the humidity at comfortable levels in both summer and winter. This is a delicate balance: if humidity is too low, you’ll feel the effects of colds, respiratory infections, and asthma more, and some of the furnishings in your home can literally dry out. If humidity is too high, you’ll be uncomfortable, and mold and mildew will flourish.  Proper humidity levels keep you healthier and more comfortable.

Humidity refers to the amount of water vapor in the air.  Warm air holds more water vapor than cold air.  This explains why you will experience high humidity in the summer and low humidity in the winter.

Problems with high humidity:
When the temperatures warm up outside you can experience too much humidity in your home. Too much humidity can cause condensation on windows, wet stains on walls and ceilings, moldy bathrooms, musty odor, and/or a clammy feel to the air. Rot and structural damage can also result from extended periods of high humidity in your home.

High humidity can be especially dangerous when combined with high temperatures, as it will disrupt the body’s ability to cool itself, which can lead to heat stroke. People with heart problems or asthma are advised to be extremely careful during such conditions. Drier air provides comfort at higher temperatures, so homeowners can raise the setting on their central air conditioners thereby reducing their energy usage.

High humidity can even trigger allergic reactions, contribute to ongoing allergies, and dust mite problems. High humidity makes it easier for molds to reproduce, and they can appear virtually anywhere, damaging whatever they grow upon. Mold spores pose a threat for allergy and asthma sufferers. Dust mites will thrive when the humidity is high. Present in almost every home, these tiny pests are yet another nuisance for people with allergies and asthma.

Solutions for high humidity:

  • Air conditioners pull moisture from the air as they cool it, which is one reason you feel better in an air conditioned home
  • Install a dehumidifier directly to your heating and cooling system or purchase individual units for rooms or areas in your home*
  • Turn down or stop using your humidifier
  • Vent areas that create moist air, like the shower or bathroom
  • Use range and bathroom exhaust fans while cooking and bathing
  • Cook with pots and pans covered
  • Take shorter showers with cooler water
  • Install fresh air intake duct
  • Reduce the number of plants in your home
  • Vent the clothes drier to outside
  • Air conditioning– make sure your air conditioner is sized correctly; when it runs, it may run a little longer, but it will be pulling out moisture and will have an easier time cooling so it’s not costing you any more (Rule of thumb: size = one ton of air conditioning for every 600 square feet of indoor space)
  • Add carpet – this will actually trap moisture

Problems with low humidity:
When the temperature outside falls, your furnace runs more. In extreme cold conditions, your home humidity level can drop as low as 10 percent. By comparison, the Sahara Desert has an average relative humidity of 25 percent. When you consider that people generally are most comfortable when the relative humidity is approximately 40 percent, you can see how dry indoor air can take a toll on your family.

Low humidity causes static electricity, dry skin, lips and hair, scratchy throats and noses, and itching and chapping. Mucous membranes in nose and throat dry out, increasing your discomfort and susceptibility to colds and respiratory illness. With low humidity levels, body moisture evaporates so quickly that you feel chilled even at higher thermostat settings.

Your home suffers, too. Low humidity can cause havoc with woodwork and furniture. You’ll notice shrinkage, hardwood floor separation and warping, your piano will go out of tune, wallpaper peels at the edges, drawers loosen and molding gaps start to appear.

Solutions for low humidity:  

  • Install a humidifier directly to your heating and cooling system or purchase individual units for rooms or areas in your home *
  • Boil or cook with the lids off the pans
  • Keep houseplants

*A humidifier/dehumidifier built into your heating and cooling system is the best long-term solution. The water supply is constant and it can be controlled by a humidistat mounted on your wall, properly regulating the humidity in your home. With the right amount of humidity, you’ll find that you can be comfortable at a lower thermostat setting. And that will increase your comfort as well as save you money on your energy bills.