Blog > Category Post > Posted: 2020-Jul-15, Updated: 2020-Sep-23

New ENERGY STAR climate zones for windows (2020 - present day)

Canada Window Energy Star climate zones for windows
Even though windows do not consume energy, they can be a significant source of heat loss in a home. ENERGY STAR qualified windows will save you money by reducing the overall annual energy costs. ENERGY STAR windows will also help keep your home more comfortable all-year-round and may have less condensation in cold weather compared with a conventional non-certified product.

Before we begin, here are some Energy Star Resources
for you to take a look at:

Be sure to select the ENERGY STAR Most Efficient (YEAR): checkbox to see the most efficient windows for the YEAR.

Window ENERGY STAR Ratings “Out with the old and in with the new!”

We live in a world of ever-changing and evolving products, policies and procedures - made to make our lives easier. So, it’s no surprise that the Energy Star Window Standards in Canada, and the Climate Zones areas associated with these standards have been for simplicity.

No more thinking required

The three distinct Energy Star Climate Zones that had previously existed (2015 to 2019) in Canada have now been combined into one zone. As of January 1, 2020, the Energy Star window program which includes standards for Canadian manufacturers, installation and residential home builders has been simplified. But no worries, the new zones does not mean that the specification requirements have been lowered, in fact, for areas of Canada that experience less extreme temperatures, the bar has been raised.

See the old Energy Star Climate Zones

How are ENERGY STAR ratings formalized?

In Canada, the energy performance of a window is tested using the Canadian Standards Association (CSA) A440.2 standard. And Energy Star Certification is administered by Natural Resources Canada which uses several metrics to measure the energy efficiency of window or door.

Energy performance is rated using the following values:

1. The U-factor
(The lower the number, the more efficient the product)

The U-factor is the rate of heat transfer from warm to cold areas in watts per square metre Kelvin (W/m2K) or in British thermal units per hour per square foot Fahrenheit (Btu/h x sq. ft. x °F).

2. Solar heat gain coefficient (SHGC)
(The higher the number, the more solar heat the product gains)

A solar heat gain coefficient is a ratio showing the amount of the sun’s heat that can pass through the product.

3. The R-value
(The higher the number, the more efficient the product)

The R-value is a value indicating the resistance to heat transfer in square feet per hour in degrees Fahrenheit per British thermal unit (sq. ft. x h x °F/Btu).

(The R-value is not part of the energy performance standards, but is often quoted by contractors and sales staff as a measure of performance.)

4. Visible transmittance (VT)
(The higher the number, the more light can pass through)

Visible transmittance is a ratio of the amount of visible light that can pass through a product.

5. Centre-of-glass rating

The centre-of-glass rating an energy-efficiency value refers only to the glass portion of a window product and not as a whole.

6. The Energy Rating (ER)
(The higher the number, the more efficient the product)

A value demonstrating the balance between U-factor, SHGC and air leakage. ER values can be presented in Imperial or Metric Units of measurement.

7. Air Leakage (AL)
(The lower the AL, the less air will pass through cracks in the window assembly)

The air leakage value is a heat loss and gain that occurs by infiltration through cracks in the window assembly. It is indicated by an air leakage rating (AL) expressed as the equivalent cubic feet of air passing through a square foot of window area. This rating must be 0.30 or less to qualify for Energy Star Certification.

ENERGY STAR - Minimum qualification criteria for windows

Products that earn the ENERGY STAR are independently certified to save energy, save money and protect the climate. In order to qualify for ENERGY STAR certification, a window or door must meet a minimum Energy Rating (ER) or a maximum U-Factor value.

Minimum Energy Rating (ER) or Maximum U-Factor/Minimum ER
34 or ≤ 0.21

ENERGY STAR - Most Efficient Windows

Energy Star recognizes and publishes a LIST of the most efficient windows, a distinction recognizing products that deliver cutting edge energy efficiency along with the latest in technological innovation. It is an award that truly represents the best of ENERGY STAR.

To qualify, these products must exceed the minimum qualification criteria and meet or exceed a minimum ER rating and U-factor value.

Minimum Energy Rating (ER) or Maximum U-Factor/Minimum ER
40 or ≤ 0.18

Check the specs (not all windows brands are the same)


Be careful when checking window ratings, some companies will put their best foot forward by making general statements about their windows based on a single best performing window. These statements may mislead the buyer into believing that all their windows meet the “Energy Star Most Efficient List”.


Fixed picture windows often perform better than operational windows. So if you want to ensure that you are getting a window that is recognized for efficiency in the ENERGY STAR - Most Efficient Windows list, make sure you check the specs for each window type that you are looking to purchase.

Who does the ENERGY STAR certification?

When you buy ENERGY STAR certified windows, they have been tested against current Energy Star standards by an accredited laboratory, and the test results are verified by an independent third party. Windows sold in Canada may be certified for energy performance by:

  • CSA International (CSA)
  • Intertek Testing Services (ITS)
  • Quality Auditing Institute Ltd. (QAI)
  • The National Fenestration Rating Council (NFRC)
  • Labtest Certifications

What about Insulated Glass Units (IGUs)

Some insulated glass units may carry Insulating Glass Manufacturers Alliance (IGMA) certification - IGUs that will not fog and whose seals will not fail prematurely. Certification does not come from the Energy Star program.

This program promotes the consistent production of high-quality Insulating Glass Units. Each product line undergoes rigorous testing against the Canadian General Standards Board (CGSB) 12.8 Standard for Insulating Glass Units and the manufacturer must maintain a quality control program approved by IGMAC. In addition, each product line is independently audited at least twice a year and retested every two years.

Need more information?

We can help deliver a product that will genuinely change your homes carbon footprint. We offer a wide selection of windows and doors that exceed the new Canadian (January 1, 2020) ENERGY STAR” standards and “ the current year’s ENERGY STAR Most Efficient windows” for the Energy Star Program and can ensure that you find the perfect product for your vision.

Understanding window ratings:

Got more questions?

If you would like to know more, give us a call or send us a request for more information. We’d be happy to address all of your questions or concerns. Contact Us.