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The Ultimate Guide to Energy-Efficient Windows in Ontario

By Apex Expert Team | March 12, 2026

With the fluctuating climate of Southern Ontario, choosing energy-efficient windows is one of the best investments you can make. But with so many technical terms like U-factor, solar heat gain, and R-value, it's easy to get overwhelmed.

Energy efficient window testing in Ontario

1. Understanding the U-Factor

The U-factor measures how well a window prevents heat from escaping. The lower the number, the better the window is at keeping heat inside during the winter. For Ontario homes, we recommend a U-factor of 1.2 or lower.

2. Low-E Coatings and Argon Gas

Modern efficiency comes from invisible Low-E (Low Emissivity) coatings that reflect heat back to its source. Combined with Argon gas between the panes, these windows act like a thermos for your home, keeping it warm in winter and cool in summer.

3. 2026 Energy Rebates

Don't forget that many municipal and federal programs in 2026 offer rebates for upgrading to Energy Star certified windows. These programs can often cover a significant portion of your installation costs.

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Expert advice on window selection and rebate guidance. Apex Windows & Exteriors is your partner in energy efficiency.

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