Moderate your indoor humidity in winter

If water condenses on your windows in winter, the problem might not be the windows – it might be that the house is too humid.

Time

1-2 hours

Difficulty

Easy

Expertise

None

Frequency

Once a year

Where

All US

Overview

Humidity makes your home more comfortable in winter, but you can have too much of a good thing. When you see condensation on your windows in wintertime, it’s a sign that you should lower the humidity level in your house. Otherwise, the water that condenses on your windows – not to mention inside your walls – can cause damage over time.

Try these suggestions for reducing humidity levels.

Steps

1. Reduce moisture sources within your house:
   • Don't store firewood in the home.
   • Repair foundation leaks.
   • Turn your humidifier down or off.
   • Cover any exposed earth floor in a basement or crawl space, as well as sump pits.
   • Don't hang laundry to dry inside your home.
   • Limit the use of vaporizers or steam generators.
2. Ventilate your home:
   • Vent your clothes dryer to the outside.
   • Use exhaust fans when showering or cooking.
   • Install a heat recovery ventilator (HRV) to exhaust warm moist air from your house and replace it with dry, fresh air from outdoors.
3. Adjust the humidifier on your furnace, based on the outdoor temperature:
   • -20 degrees F. — 15%
   • -20 to -10 degrees F. — 20%
   • -10 to 0 degrees F. — 25%
   • 0 to +10 degrees F. — 35%
   • +10 and above degrees F. — 40%