Energy Star And NFRC Efficiency Ratings

ENERGY STARĀ® is a voluntary arrangement between Natural Resources Canada’s Office of Energy Efficiency and organizations that manufacture, sell or promote products designed to help businesses and consumers save money and protect the environment through energy efficient products and practices. Learn more about ENERGY STARĀ®.

The National Fenestration Rating Council (NFRC) is the leader in energy performance rating and certification programs for fenestration products and is recognized as the certification body for the Energy Star program. Learn more about NFRC.

Click the link below to determine which combination of window style and insulating glass option is most suited to your environment and lifestyle. Simply choose your Window Style and Glass Type to configure your windows:

Understanding the chart headings

Divider Type– Refers to the kind of grille. Insulating Glass Unit (IGU) between-the-glass grilles are metal and Simulated Divided Lites (SDL) external grilles are vinyl. Both types of grilles affect thermal and light transmission.

System – 3000 Series is 3 1/4″ deep, 4000 Series is 4 9/16″ deep.

CPD# – A Certified Products Directory number identifies products that pass strict NFRC guidelines.

U-Factor – Thermal Transmittance (Imperial or Metric measurement) is the rate of transfer of heat. The lower the number the less heat transfer.

SHGC – Solar Heat Gain Coefficient is the fraction of incident solar radiation admitted through a window. The lower a window’s solar heat gain coefficient, the less solar heat it transmits.

VT – Visible Transmittance is the amount of visible light transmitted through a window. The higher the number the more light is transmitted.

Comfortable home


CR – Condensation Resistance measures how well a window resist the formation of condensation on the inside of the window. The higher the number, the better the resistance.

ER – Refer to Performance chart.

Zones (Canada) – Click map below to enlarge.
Energy zone map