Are there any government or industry standards for window companies?
Yes, you should always insist that you see both the CSA and ENERGY STAR® labels or standards for every window or door you consider buying.
Certifications & Standards
What is ENERGY STAR?
ENERGY STAR is an international symbol of energy efficiency.
The ENERGY STAR symbol helps consumers quickly and easily identify major appliances and other energy-using equipment that save energy. ENERGY STAR identifies products as the top high efficiency performer in their category.
ENERGY STAR is a dynamic government/industry partnership that makes it easy for businesses and consumers to save money and protect the environment.
How do products qualify for the ENERGY STAR mark?
ENERGY STAR certified products must meet and exceed minimum Canadian federal energy efficiency standards according to a prescribed performance level for each product area.
Why buy ENERGY STAR certified products?
By choosing ENERGY STAR certified products, buyers save energy and money on utility bills, and reduce air pollution without sacrificing the features, versatility or style they expect from high-performing products.
Canada has been divided into four climate zones based on annual average temperature. Zone A is the mildest, and Zone D is the coldest.
Make sure that the product model you are buying is certified for the correct climate zone, or, to save even more energy, for colder zones. If you live in a location that is significantly higher in elevation than the surrounding area, consider purchasing a product that is ENERGY STAR certified for at least one zone colder than where you live (especially in southern and central British Columbia).
ENERGY STAR certified windows, doors, and skylights are tested and certified by an independent, accredited agency. Products qualify for ENERGY STAR based on either their U-value or their Energy Rating.
A U-Value indicates the rate of heat transfer. The lower the U-Value number, the slower it transfers heat from a warm area to a cold area.
Solar Heat Gain Coefficient
The solar heat gain coefficient (SHGC) indicates the amount of solar gain through a pane of glass. It ranges from 0 to 100. The higher the number, the better the solar gain.
Visible Transmittance (VT) determines the amount of light coming through a window. A scale from 0-1 is used, but most values fall within .25-.80. More natural light passes through windows with a higher VT.
The Energy Rating (ER) value is calculated using a formula that balances a product's U-Value with its potential solar heat gain coefficient (SHGC) and its airtightness. The higher the number, the more energy efficient the product. The ER scale was recently modified so that all products now have a rating of between 0 and about 50. (Under the previous rating scale, it was possible for a product to have a negative ER number.) The higher the ER number, the better the product's thermal performance.
Canadian Standards Association (CSA) - Specifications for Centennial Windows
ENERGY STAR Specifications - Specifications for Centennial Windows
Canadian Window and Door Manufacturers Association (CWDMA) - "Sill to Sash"
Natural Resources Canada - General Information