How to Choose an Energy-Efficient Window

In this article, you will learn:

1.What Makes an Energy-Efficient Window?
2. Understanding ENERGY STAR Ratings
3. 6 Benefits of ENERGY STAR Certified Windows

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When shopping for residential windows, energy-efficiency should be the #1 priority!

From improving temperature regulation and energy consumption to utility bills and even property value – energy-saving windows are an excellent way to improve the quality and comfort of your home.

With a variety of styles, configurations and price points to choose from, it can sometimes feel a bit overwhelming to determine the best window option for you!

While inefficient windows can account for up to 25% of internal heat loss, selecting products that have been ENERGY STAR certified can help Canadian homeowners identify the most reliable window options on the market. 

At Simpson Windows and Doors, we encourage product education to help our clients get the most out of their homes.

The following article will help you identify the components of an energy-efficient window, learn how ENERGY STAR certifications are rated and the 6 benefits of selecting ENERGY STAR certified products.

What Makes an Energy-Efficient Window?

The difference between an efficient and inefficient window is whether or not it can prevent air from entering or escaping your home.

With a variety of customizable parts, an energy-efficient window relies on the combination of materials, installation and maintenance to ensure that they are always performing as they should. 

Through a balance of functionality, style and energy-saving capabilities, an energy-efficient window is made up of the following components:

1. Framing Materials:

ENERGY STAR certified windows can come in a variety of different framing materials.

With styles, colours and designs to suit just about any interior design, homeowners have the option of:

  • Fiberglass Window Frames – strong, durable and low maintenance. Available hollow or filled with foam insulation.
  • Vinyl Window Frames – affordable, low maintenance with good thermal insulation. Also available hollow or filled with foam insulation.
  • Aluminum Window Frames – durable, recyclable and low maintenance. Typically include thermal breaks to reduce conductive heat loss.
  • Wooden Window Frames – strong, secure and provides great thermal insulation. Popular in historical homes.
  • Combination Window Frames – using a combination of materials to enhance performance.
  • Composite Window Frames – durable, low maintenance, rot-resistant and well-insulated. Made from a variety of materials blended together.

2. Multi Pane Glass:

Energy-efficient windows are typically made up of double-paned or triple-paned glass.

These multilayer sheets create air-tight pockets to prevent air from entering or escaping your home, fluctuating internal temperatures or increasing energy expenses.

3. Glass Coatings/Glazing:

As different windows in your home may be exposed to different conditions (such as sunlight or frequent shade), glass coatings or glazings can be applied to improve the overall energy-efficiency of your windows.

Three common glass coatings include:

  • Insulated Window Glazing – used to improve the U-factor by sealing the airspace between two or more panes of glass.
  • Low-Emissivity Coatings – used to limit ultraviolet and infrared light from the sun by 30-50% while still allowing sunlight to pass through.
  • Spectrally Selective Coatings – a special type of low-E coating used to filter out an additional  40-70% of heat without impacting the amount of light that shines through.

4. Gas Fills:

Energy-saving windows will often use non-toxic, colourless and odorless gas fills between the window panes to minimize heat transfer and increase insulation:

  • Argon – affordable and most commonly used. 6 times denser than air.
  • Krypton – more expensive, but provides better insulation. 12 times denser than air.

5. Window Spacers:

For windows that are filled with gas, spacers will be inserted between the layers to keep them the correct distance apart.

Available in non-metal or metal-hybrid materials, these spacers insulate the window pane edges to prevent the risk of moisture leaks, gas leaks and/or heat transfer.

6. Installation Process:

While energy-efficient materials are half the battle, a professional installation can make or break a window’s performance.

In fact, an incorrect installation process can often result in air leaks, water damage, increased energy bills and expensive repair projects.

At Simpson Windows and Doors, we are committed to quality service that will protect you and your family for many years to come.

Understanding Energy Star Ratings

When a window product displays a blue ENERGY STAR symbol, they are communicating that they have been:

a. Manufactured by an ENERGY STAR partner

b. Independently tested, certified and verified by the National Fenestration Rating Council (NFRC) and,

c. Approved by the US Environmental Protection Agency (EPA) through NFRC ratings that meet strict energy efficiency guidelines

NFRC ratings are included on all ENERGY STAR certified windows, providing Canadian homeowners with a reliable way to identify a window’s energy properties.

By comparing energy performance ratings, you should be able to determine how much heat or sunlight each window might transmit into your home!

These performance ratings are broken down into the following 5 categories:

1. U-Factor:

The U-Factor (or U-Value) of a window represents the rate of heat loss.

While energy-efficient double-pane windows possess U-Factors of 0.30 or lower, triple-pane windows are able to achieve U-Factors of 0.15.

When looking for an energy-efficient window, lower U-Factors will offer higher insulation performance, making them more resistant to heat loss.

2. Solar Heat Gain Coefficient:

The Solar Heat Gain Coefficient (SHGC) measures how well a window can block out heat produced by sunlight.

Measured in values between 0 and 1, the average range of windows typically sits between 0.25 to 0.80 with lower scores resulting in less solar heat transmitted.

3. Visible Transmittance:

Visible Transmittance (VT) is the measurement of light that gets pushed through a glass window.

Similar to the Solar Heat Gain Coefficient (SHGC), VT is measured between values of 0 and 1 with the average range also sitting around 0.20 to 0.80.

Unlike the SHGC however, a higher VT score would be associated with a more energy-efficient window as this would allow the most amount of light into the home.

4. Condensation Resistance:

Condensation resistance, scored between 0 and 100, is the measurement of how well a window can hold up against water build-up.

When shopping for residential windows, it is important to search for windows with a higher CR factor as these will better protect your home from water leakage, damage and mold.

5. Air Leakage:

The Air Leakage (AL) of a window is the measurement of air that travels through one square foot of window area per minute.

While the industry standard for building code is an AL of 0.3 cf-m/ft², lower AL values will provide less air leakage and higher performance efficiency. 

6 Benefits of Energy Star Certified Windows

Although there are a wide variety of window manufacturers on the market today, it is important to note that not all of their products will be ENERGY STAR certified.

While we encourage Canadian homeowners to compare all of the above listed details when shopping for residential windows, choosing products with an ENERGY STAR certified symbol can provide the following list of benefits:

  1. Time-Saving: Searching for the ENERGY STAR symbol can help Canadian homeowners identify top energy performing windows.
  2. Energy-Saving: ENERGY STAR rated windows are typically ranked within the top 15-30% for energy performance.
  3. Money-Saving: By reducing your energy consumption, ENERGY STAR certified windows have been able to save an average of 12% on annual utility costs.
  4. Environment-Saving: Reducing the amount of energy used in your home will also reduce the amount of greenhouse gas emissions put into the atmosphere.
  5. Tested and Certified: As each ENERGY STAR certified product is tested and certified to meet strict efficiency standards, Canadian homeowners can rest assured that their windows will perform for many years to come.
  6. Guaranteed High-Quality: Designed for quality and efficiency, ENERGY STAR certified windows guarantee high-quality performance with industry-leading warranties.

If you are interested in learning more about your window replacement options, allow our trained professionals at Simpson Windows and Doors to help!

Click here or call us at 905-853-2519 for a complimentary consultation.

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