Building Envelope

Insulation – Attic

Insulation helps keep outdoor air from getting inside your home. It also prevents indoor air from escaping. For maximum energy efficiency, attics should be sealed, insulated, and ventilated.

Air leaks in your attic will cause substantial heat loss and lead to a variety of moisture-related problems in your home.

What to Look For

  • Insulation is rated by its R-value. “R” stands for resistance and the higher the R-value, the more efficiently it resists the transfer of heat from one area to another.
  • Different types of insulation have different R-values, but you can combine them to achieve a higher overall rating.
  • The recommended R-value for attic insulation in Ontario is between R-50 to R-60.
  • The most common types of insulation used in attics are spray form, loose-fill, and batt and blanket insulation.

Things to Consider

  • Ensure your project meets the minimum R-Value needed to receive available rebates.
  • Hire a professional. Improper installation can lower the R-value of the material, and there are health and safety measures that must be considered.
  • Before you purchase new insulation, get an home evaluation and check with your municipality, utility or retailer to see if rebates are available.


$1.50 to $3.50/sq. ft.

Source: Natural Resources Canada