Too Humid or Too Dry?

For a healthy and comfortable home, keep indoor humidity levels within a reasonable range (25–35 per cent in the coldest weather).

Here are some things you can do to adjust the humidity levels in your home:

• To reduce the amount of moisture produced in the house:
  • turn humidifiers down or off;
  • don't hang clothes indoors to dry;
  • vent the clothes dryer to the outdoors;
  • take shorter showers or baths if you don't have an exhaust fan;
  • cover exposed earth in basements or crawlspaces with a moisture barrier;
  • improve drainage around the foundation.
• To improve air circulation:
  • open drapes or blinds over windows;
  • move furniture or objects blocking warm and cold air registers;
  • remove heat deflectors to allow warm air to flow over windows;
  • run the furnace fan continuously at low speed.
• To improve ventilation:
  • use the kitchen exhaust fan while cooking;
  • use the bathroom exhaust fan while showering or bathing and for 10 minutes after;
  • install a dehumidistat or timer switch to keep the bathroom fan on until it has exhausted excess humidity;
  • make sure exhaust fans vent to the outdoors or that the vent hood is not blocked shut;
  • install and use exhaust fans in the kitchen and washrooms;
  • install and use a heat recovery ventilator (when all other options are attempted).

Increasing humidity in the home is much easier than reducing it. If your house is too dry, try the following to raise humidity:

• Seal and weather strip your home to reduce air leakage. Cold, dry air from outdoors will “soak” up humidity. Reducing drafts also improves comfort, lowers your heating bills, and may even reduce or eliminate the need for a humidifier.
• Use a portable humidifier.
• Install a furnace humidifier (if your home has a forced-air heating system).

To achieve the right level of humidity in your home, read our Home Comfort and Energy Efficiency booklets #1, 2, 5 and 8 for more information on indoor air quality, ventilation, air sealing and insulation.