What Is The Energy Star Rating and Why Does It Matter?

December 29, 2022


Energy Efficiency

What Is The Energy Star Rating - Clera Windows + Doors

Nowadays, having energy-efficient windows is crucial to lowering your bills, preventing drafts or air leakage, and helping you save the environment. Energy-efficient products have been helping Canadians save thousands of dollars for decades, and with new improvements to technology being made every year, this can only benefit more people in the long run.

One of the main ways in which products are rated for their energy efficiency is with the ENERGY STAR certification. This is an important standard that is widely used in the United States and Canada, and is applied to a range of products to show how energy-efficient it is.

But what is the Energy Star certification? How is this rating justified, and why should Canadian homeowners care? We’ve put together this guide to help you understand what an Energy Star rating is, and why it matters.

What Is an Energy Star Rating?

Energy Star is a United States government-backed symbol developed in conjunction with the Environmental Protection Agency (EPA). It is designed to help consumers identify products that have met certain efficiency requirements, which lets them make informed decisions to help save money as well.

Since its inception in 1992, Energy Star has been used by Fortune 500 companies and has helped save five trillion kilowatt hours in the United States alone.

The Energy Star logo

What Makes Energy Star Windows Energy Efficient?

With over 90% of consumers recognizing the Energy Star symbol, it is an extremely useful tool to aid in the search for the best energy efficient windows in Ontario. But what makes these certified windows great?

Energy Star products are made of low-maintenance materials, specially designed for maximum insulation as well as durability.

The glass is of Low-E quality, which not only reflects infrared light to keep heat inside during the winter and outside during the summer, but also stops the ultraviolet light from reaching the upholstery, such as seats and carpets. 

Between the panes in some certified windows is a special type of gas (either argon or krypton) that is odourless, colourless, non-toxic and a better insulator than regular air. 

There is also a warm edge spacer at the point of attachment between the glasses and the frame, which keeps the panes separated by the right margin and insulated at the edges to minimize transfer of heat between them.

How Are Window Energy Ratings Measured?

Energy Star window ratings will vary depending on different attributes. For example, in order for a washing machine to be given the certification, it would need to use 25% less energy and 33% less water than normal washing machines on the market.

For windows, the energy ratings are tested using the latest Canadian Standards Association (CSA) A440.2 standard.

How Are Window Energy Ratings Measured - Clera Windows + Doors

Additionally, some products sold in Canada may also be inspected according to the standards of the National Fenestration Rating Council. This is a non-profit organization based in the United States that provides consumers with energy performance ratings specifically for windows, doors, and skylights.

According to Natural Resources Canada, energy performance ratings are evaluated using the following:


U-factor refers to the rate of non-solar heat transfer from warm to cold areas. Basically, it tells you how well a window, door, or skylight insulates. It ranges from 0.25 to 1.25 watts per square metre Kelvin (W/m2K). The lower the U-factor, the better.

Solar Heat Gain Coefficient (SHGC)

SHGC numbers illustrate the ratio or the fraction of solar radiation that is transmitted directly to and absorbed by the windows, and released as heat inside the house. A lower SHGC rating indicates excellent shading ability, which is great during summer months because it will block the heat emitted from the sun

On the other hand, a high SHGC rating will keep the home warm during the cold winter season. Your home’s location, climate, and external shading will all play a pivotal role in determining the best SHGC rating for you.

Centre of Glass Rating

As the name suggests, this specifically measures the energy efficiency rating of the glass portion of windows, doors, and skylights.

Visible Transmittance (VT)

Visible transmittance is an optical criteria and is different from SHGC. It measures a fraction of the amount of visible light that can pass through the glazing material of a window. A higher VT means a window can usher in plenty of natural light

When designed smartly, your home will be able to maximize daylight and conserve energy.

Why Are Energy Star Windows Preferred in Canada?

The core purpose of Energy Star in Canada is to help the country save energy by encouraging manufacturers to produce “greener” products through “greener” solutions. However, consumers have been the biggest beneficiaries of the whole program.

Why Are Energy Star Windows Preferred In Canada - Clera Windows + Doors

4 Benefits of an Energy Star Window

Windows are important features of any home. They allow you to control the natural lighting and temperature inside any space, while providing ample visibility to the surrounding environment. 

Windows that are certified have been tested to ensure that they minimize heat loss and air leakage. But what are the other benefits of an Energy Star-certified window?

1. Cost Savings

Certified windows help reduce the cost of your energy bills each month. The more efficient your windows and doors are, the less energy is required to cool and/or heat your home.

When compared to non-certified windows, Energy Star products reduce energy costs by approximately 12%. The amount you’ll save will depend on your local weather conditions, home design, and utility costs.

2. Increased Comfort

Using high-quality windows, doors, and other products helps you create a consistent temperature throughout your entire home—even under extreme weather conditions.

Windows that aren’t energy-efficient will typically pull heat away from anyone sitting nearby. Energy Star windows prevent this heat loss, as its surface stays warm during cold outdoor temperatures. Inversely, certified windows keep out the heat so that you can stay cool during the hot summer months.

3. Home Protection

Your home’s windows can make its interior vulnerable to damage from sunlight. Windows that are certified have a unique coating that protects your interior from harmful ultraviolet (UV) light.

It’s not uncommon for damage to occur to wood floors, curtains, and personal possessions when exposed to the sun’s UV rays. Energy Star windows protect these items from losing their colour and integrity over time.

4. Tax Credit

Homeowners in Canada may receive an energy efficiency tax credit equaling 10% of the product’s cost.

Learn more about government rebates for replacement windows.

Best Energy-efficient Windows - Clera Windows + Doors

Get the Best Energy-Efficient Windows With Clera

Are you looking to replace your windows in Ontario with more energy-efficient ones? You could save thousands on your energy bill in no time with Clera Windows and Doors!

Contact us today and one of our experts will help you choose the perfect windows for your home.

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