Blog > Category Post > Updated: 2017-Dec-26

What is an Energy Star Energy Rating?

The higher the ER rating number, the more energy-efficient the window or door.
Although windows and doors do not consume energy, they can be a significant source of energy loss. If you are buying windows with energy efficiency in mind, then the ER will help you make standardized window product comparisons.

For apples-to-apples comparisons

Energy Star certified products are tested by authorized neutral organizations using a standardized procedure to meet strict efficiency specifications that make it easier to compare similar products from different companies.

With energy-efficiency in mind, Energy Star certified windows can save you money on your energy bills and help contribute collectively to reducing carbon emissions.

According to Natural Resource Canada (August 2017), Energy Star certified windows can save you an average of 8% on your energy bills as compared to standard windows. Windows that qualify for Energy Star’s most efficient windows are up to 40% more efficient than a standard window.

Want to window comparisons? Take a look at Energy Star’s most efficient window products.

The Energy Star certification (CSA A440.2 Standard) process measures 3 variables that are applied to a formula that calculates a windows Energy Rating (ER):

  1. U-factor (UF) - heat loss through frames, spacer and glass
  2. Solar heat gain coefficient (SHGC) - heat transmitted and absorbed and subsequently released inward
  3. Air leakage (AL) - cold air hot air moving through the window or door

These variables are factored into Energy Star’s Energy Rating (ER) - a unitless value that represents the overall energy efficiency performance of the window or door being tested.

Energy Star summary for Ottawa:

  • The larger the ER rating number, the more energy-efficient the window.

Want to know if you are getting the most energy efficient window? Talk to your local window specialist. They’ll help you find the perfect window, that will maximize your home comfort and minimize your energy costs.