Find the Moisture Level in Your House

The amount of moisture in the air is often called “relative humidity” or “RH” for short. RH is important because it provides a way to assess moisture conditions and condensation risk in a home.

Key points about relative humidity:

  • The relative humidity in a home can be measured with a hygrometer. RH measurements run from 10 per cent to 100 per cent and provide an indicator of how much moisture is in the air relative to what it can hold. Dry air has lower RH readings and moist air has higher.
  • Hygrometers can be purchased at a local hardware or building supply store. They are relatively inexpensive.
  • In very cold weather, a level of 30 per cent or lower may be needed to prevent window condensation.
  • In the winter heating season, the relative humidity should not exceed 45 per cent.
  • Upgraded, energy-efficient windows can support a higher level of relative humidity without condensation occurring.
  • Low RH is good for controlling moisture but can be a comfort problem for household members. Low RH can be associated with dry eyes and nasal and throat discomfort.
A hygrometer
A hygrometer is an instrument used for measuring the moisture content in the atmosphere.
Window with condensation Moisture condenses when cold surfaces meet warm moist air. Condensation will make surfaces wet, which can cause water damage or help mould/mildew grow.



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