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Choosing Energy Efficient Windows For Ontario Homes & Cottages

| June 15, 2021
energy efficient windows for ontario


Ontarians should be able to count on their windows year-round.

Over the course of a given year, Ontarians contend with a wide range of weather conditions — hot, humid summers; wet, frigid winters; springs that can bring wind, rain, snow, and sun all in the same week. As a result, energy efficient windows for Ontario homes and cottages are important for two reasons:

  1. They help your home or cottage stay sealed from the elements, regardless of the fluctuations in weather.
  2. They help ensure that the energy generated by your home is not wasted.

energy efficient windows for ontario

Window-related energy waste should not be overlooked

Aging, faulty, leaky, improperly sealed windows can be a major source of unnecessary heat loss, high home energy consumption, cold drafts, and issues with condensation. In fact, windows can account for up to 25 percent of the total heat loss for a home. It’s important to keep an eye on your windows and ask yourself:

If you notice any of the above, it’s time to seriously consider window replacement.

Investing in modern, energy-efficient windows just makes sense long-term

Whether you’re having issues with your home or cottage windows or you’re just looking for a more modern look, investing in high-performance units simply makes the most sense. While proper efficiency can be more of an investment upfront, it’s one that will help you save time and money in the long run.

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Energy Efficient Windows for Homes & Cottages: Here’s What to Look For

Purchasing energy efficient windows for Ontario homes and cottages should start with asking the right questions. Rather than simply looking at cost and yielding to high-pressure sales tactics, educating yourself on what makes windows efficient leads to smarter purchasing decisions.

Here are four key factors that every home or cottage owner should consider when purchasing new windows.

1. The Right Third-Party Certification

The claims made by sales representatives should always be backed up by solid facts from third-party organizations. For windows, the National Fenestration Rating Council (NFRC) provides homeowners with reliable third-party information about energy-efficient windows. They have established objective energy performance ratings for windows, doors, and skylights. These ratings are intended to help you compare products and make informed purchasing decisions in three key ways:

  1. Communicating the energy performance of products using the NFRC label
  2. Helping you understand the different categories of energy performance
  3. Providing tips, tools, and educational resources about windows, doors, and skylights.

energy efficient windows for ontario

2. The Metrics that Gauge a Window’s Energy Efficiency Capabilities

The NFRC label provides standardized ratings in four key energy performance categories.


U-factor determines the rate at which heat escapes through a window. The lower the U-factor number is, the better the window is at mitigating heat loss.

Solar Heat Gain Coefficient

This metric determines how well a window can resist heat gain. The lower the number, the less heat enters via the window. SHGC ranges between 0 and 1 and windows are generally between 0.25 and 0.8.

Unlike the other energy efficiency metrics used by the NFRC, a “good” or “bad” Solar Heat Gain Coefficient rating largely depends on the climate where the home is located. For homes in Northern Canada exposed to long winters and minimal warm weather would want a higher SHGC to take advantage of more solar heat gain. Conversely, a lower SHGC is essential in the Southwestern United States, where homes are exposed to ample sunshine year-round. Put simply, a lower SHGC can reduce cooling costs, while a higher SHGC can reduce heating costs.

Air Leakage

Air leakage infiltration measures the amount of airflow into the building via the window and exfiltration is the flow of air out of the building. The lower the number, the better your windows will be at preventing unwanted airflow.

Visible Transmittance

This metric determines how well a window permits the flow of natural light into a home. The higher the VT, the better. By allowing more natural light, a window helps reduce the need for artificial light sources.

3. Window Features That Improve Energy-Efficiency Metrics

Now that we have an understanding of the metrics used to gauge a window’s efficiency, let’s look at the features that affect these ratings.

Low Emissivity (Low-E) Window Glass Coatings

Affects: Solar Heat Gain Coefficient

This transparent, incredibly thin coating helps the window reflect unwanted solar heat, allowing spaces to cool more efficiently in warmer temperatures. It also reflects the radiant heat emitted by objects inside the home (such as an HVAC unit) back into the home or cottage. This helps reduce heat loss during the colder months.

Low-E coating is effective because it can be tailored to deliver the right SHGC rating for specific climate regions. In warmer climates, for instance, the glass can be formulated with a heavy Low-E coating such as Guardian’s Sunguard 62/27 that will significantly reduce the amount of heat coming through the glass. In Southern Ontario, where the weather changes drastically from hot to cold over the year, a balanced Low-E formula such as the ClimaGuard 70/36 is best. It’s designed to allow you to take advantage of the sun’s heat in the winter, while not having it be overwhelming in the summer months.

Ultimately, the right window replacement representative should be able to help you determine the best Low-E formula for your home.

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Gas Fills

Help to Address: U-Factor

Gas fills are an essential step in creating an insulated glass unit. Manufacturers fill the space between the glass units with krypton, argon, or xenon gas. These heavier, noble gases are preferable to filling the unit with air because they can better impede the transfer of heat through a window.

Most IGUs on the market are separated by ½ – ¾ of an inch. Due to our innovative approach to window hardware design, we are able to extend that space to a full inch. This means we can fill our IGUs with 25%-50% more gas. More gas leads to more effective insulation when you really need it.

Warm Edge Spacers

Help to Address: Seal Failure

Warm Edge Spacers insulate the edges of the window unit and keep the glass panes firmly apart from each other. These spacers add structural stability and mitigate the stress that comes with thermal expansion and contraction in different weather conditions. By expanding and contracting at the same rate as the insulated glass unit, they help to prevent any gas from escaping and the window’s seal from failing.

Retractable Insect Screens & Blinds

Help to Address: Visible Transmittance

Insect screens can be a major asset: they block unwanted infiltration and bugs from the outside when the window unit is open. That said, traditional fixed screens collect dirt, dust, and allergens over time. And what about when the unit is closed in the colder months? While they seem benign, fixed screens can block up to 50% of the natural light that flows into a home or cottage.

Conversely, retractable screens give you complete control over when, where, and to what extent your screens are in use. With a 50% improvement in VT, the difference will be hard to ignore. Plus, with the addition of retractable solar shades and blackout blinds, you can also see improvements to Solar Heat Gain Coefficient. The use of all three Retractable Slide ‘N’ Hide® screens can lead to significant improvements in your ability to control natural light and heat.

energy efficient windows for ontario

If you’d like information on our NFRC energy ratings, visit their directory and search “CTW”.

4. Frames That Offer Strength and Efficiency

While they are popular in the industry for their excellent efficiency and their lower upfront cost, vinyl PVC frames lack strength, rigidity, and durability. They are highly susceptible to wear and tear as well as expansion and contraction in fluctuating climates. As a result, traditional hollow vinyl frames are not a smart investment if you care about long-term, maintenance-free performance.

On the other hand, our Hybrid Fusion Frame design uses a skeleton of steel and aluminum wrapped in vinyl (U-PVC). In this way, we provide the best of both worlds: the strength and durability of steel and aluminum with the efficiency of high-performing U-PVC. Our frames adapt to weather fluctuations, keeping homes and cottages better insulated year-round. These frames also come standard with a slim design to reduce the frame’s size and maximize the glass surface to create a more contemporary look.

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5. Custom Glass Formulation for Optimal Window Performance

We have been manufacturing windows for over 40 years. Over that time, we’ve come to understand the unique seasonal and environmental circumstances that home and cottage owners in Ontario have to deal with year-round. That’s why we design, formulate and manufacture our own glass units in-house, as opposed to many other replacement window companies that outsource manufacturing and production.

As a result of this decision, we can provide Ontario home and cottage owners with a variety of customizable options that they can consider for their space, including glass types, gas fills, glazings, and Low-E coatings. The customization of our glass units allows us to maximize every window’s performance in accordance with climate, building construction, and personal preference.

When it comes time to replace your windows, choose efficiency.

If you’re in the market for energy-efficient windows for Ontario homes and cottages, we offer premium designs that can elevate the look, feel, and efficiency of your home or cottage. We design our windows to be as energy-efficient as possible, and all of our units meet the rigorous standards of the National Fenestration Rating Council.

Ready to learn more? Book a free, no-hassle consultation with one of our knowledgeable representatives. They will walk you through the window replacement process and help you gain an even clearer understanding of our innovative, efficient designs.


Learn more about window replacement on our blog!

  1. Canada Greener Homes Grant: Upgrade to Energy Efficient Windows
  2. This Window Energy Rating is Flawed: Here’s Why
  3. The Benefits of Retractable Window Screens and Blinds
  4. 6 Ways to Tell if You Need to Repair of Replace Windows
  5. Why Crank Operated Casement Windows are Mechanically Flawed
  6. 4 Stunning Panoramic Window Walls
  7. The Main Issue With Hollow Vinyl Replacement Windows
  8. 3 Factors That Lead to Secure, Durable and Efficient Replacement Windows
  9. The Parts of a Window: A Guide to Window Design
  10. Is There a Best Window For Cold Weather Climates?


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