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Explained: ENERGY STAR Windows, Doors and Skylights

The blue and white energy logo is instantly recognizable. It is most commonly associated with household appliances. But the ENERGY STAR certification program is available for a wide range of goods, including windows, doors, and skylights.

Table of contents

  1. What is an ENERGY STAR?
  2. What is an ENERGY STAR window?
  3. What types of windows are most efficient?
  4. What is an ENERGY STAR door?
  5. Benefits of ENERGY STAR products
  6. Efficiency ratings in Canada
  7. ENERGY STAR zones in Canada

What is an ENERGY STAR?

The ENERGY STAR program has made making an informed eco-friendly choice easy for consumers. It condenses complex energy efficiency measurements into a single number, which lets people understand at a glance how energy efficient the product is. For appliances this can be in the form of $… per year in electricity consumption; for other products, such as windows, doors and skylights, this can be a thermal insulation rating.

ENERGY STAR is one of the most trusted marks of energy efficiency globally. It has two facets to it: first, it prescribes a set of guidelines and requirements for products; second, it standardizes the measurement of their energy efficiency.

For something to be badged ENERGY STAR, it must be tested by an independent laboratory and meet the requirements prescribed for that product. The ultimate goal is to reduce greenhouse gas emissions by reducing the inefficient use of energy.

Did you know Canada is divided into three distinct ENERGY STAR zones.

What is an ENERGY STAR window?

ENERGY STAR certified windows meet international efficiency specifications. These windows are up to 40% more efficient than non-certified windows. To tell if your windows are ENERGY STAR rated, look for the blue and white sticker or logo.

Every year, ENERGY STAR also releases a list of products that have received the ENERGY STAR Most Efficient designation. If your windows have that, it means they are amongst the most energy efficient performers.

If you live in Zone 2 or Zone 3 of Canada (see map), ENERGY STAR-certified windows will have a huge impact on your heating bills. Make sure your efficient windows are installed by professionals licensed to install ENERGY STAR rated products.

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What type of windows is the most energy efficient?


In recent years ultra-high-efficiency windows have become sought after. Though double-pane insulated windows have long been considered the standard, triple-pane windows have become exciting choices recently. They offer a near doubling of thermal performance (not the same as a doubling of temperature), and homeowners find their furnaces and air conditioners are a lot more silent.

In addition, high-quality Low-E coatings on all three panes make triple-pane (triple-glazed) windows the most energy-efficient windows. However, the most thermally insulating window may not be right for you. To understand the different aspects you must consider, find an Eco Choice representative near you.

ecochoice energy star logo

What is an ENERGY STAR-qualified door?

An ENERGY STAR qualified door is one that meets the energy efficiency requirements laid down under the ENERGY STAR program. An energy efficient door may have features such as:

  • Foam-filled insulation core
  • Compression foam seal on the edges for a perfect seal
  • Thermal break (plastic insulator in the frame)
  • Low-E coatings on glass inserts and side lights
  • Installed by a company experienced with installing ENERGY STAR products

Benefits of ENERGY STAR products

As we mentioned previously, if you are shopping for an appliance or a window, the ENERGY STAR mark is a sign that the product is more energy efficient compared to conventional products. An energy-efficient product may be a little more expensive than an ordinary inefficient one. However, you will recoup that cost (and save even more) in no time at all.

In the case of windows, doors and skylights, an energy-efficient choice will keep your home warmer in the winter (or cooler in the summer) for longer. It means your furnace and your air conditioner will run less frequently, reducing your energy bills. ENERGY STAR windows and doors also benefit from better draft protection, making your space more comfortable.

Energy ratings in Canada

In Canada, an ENERGY STAR window, door and even energy-efficient skylight must be tested using the Canadian Standards Association (CSA) A440.2 standard. Its performance is rated on six metrics (though not all products will be measured this way). We’ll also tell you if a lower number or a higher number is better. To learn more about how products qualify for ENERGY STAR, visit Natural Resources Canada (NRCAN).

  • U-factor – Rate of heat transfer from warm to cold areas (lower numbers indicate greater efficiency)
  • Coefficient of solar heat gain (SHGC) – Ratio showing how much of the sun’s heat can pass through (higher numbers indicate greater heat gains from sunlight)
  • Energy Rating – Number depicting balance between U-factor, SHGC and air leakage (higher numbers indicate a more efficient window or door)
  • R-value – Resistance to heat transfer (higher numbers indicate greater efficiency)
  • Visible transmittance – Number depicting how much visible light can pass through the product (higher numbers mean more light can pass through)
  • Centre-of-glass rating – A value that measures only the rating of the glass area of the product, not the product as a whole (lower numbers indicate greater efficiency)

ENERGY STAR zones in Canada

Not every home in Canada needs the same windows. Regions in the north of the country are colder and receive harsher winters, while the southern parts of Canada see much milder climate. Canada is divided into three climate zones. Zone 1 is reserved for relatively warmer areas, while Zone 3 comprises parts of the country that face the harshest winters. Toronto, the GTA and the Durham region all come under Zone 2.

eco choice canada energy star heat zones map

As the zone gets colder, it requires a more efficient product for it to be certified as energy efficient. For instance, a window with a U-factor rating of 1.50 would be energy efficient in Zone 1. However, it would not qualify for Zone 2, which requires a U-factor rating of 1.40 or lower.

Looking to install new windows and doors? At Eco Choice, our motto is simple: 100% customer satisfaction. That means no hidden costs, accurate estimates and being responsive to your needs. We are located in Vaughan so speak to us today and receive a free estimate for your project.