Window efficiency by window style: Does It Really Matter?

When considering window styles to maximize your home's energy efficiency, it's essential to understand how different designs can impact insulation, energy consumption, and overall comfort. Here's a comprehensive look at how various window styles perform and what you need to know to make an informed decision.

Understanding Window Efficiency

Windows play a critical role in maintaining your home's comfort and energy efficiency. While advancements in technology contribute significantly, traditional design elements also offer substantial benefits. By exploring different window types, you can find those that best enhance insulation and reduce energy consumption.

Is There a Difference?

Yes, different window styles exhibit varying levels of energy efficiency. Historically, some window types have been more efficient than others, but advancements in manufacturing have levelled the playing field. Here's a look at the efficiency rankings for vinyl windows, from most to least efficient:

Historically:

1. Picture Windows
2. Casement, Awning & Hopper Windows
3. Single & Double-hung Windows
4. Single & Double-slider Windows

Today:

Manufacturers have made significant strides in equalizing the energy efficiency of various window styles. The efficiency largely depends on the specific brand and the technology used. However, non-operational picture windows remain consistently efficient due to their fixed nature.

Comparative Analysis of Window Efficiency

A comparison of three local Ottawa window installers (listed anonymously to avoid bias) reveals that different brands can affect the energy efficiency rankings of window styles. Using data from NRC Canada Windows, each company's standard line of vinyl, double-glazed, Argon-filled windows was analyzed. The results showed that while each company's rankings varied, picture windows consistently performed best.

NRC Canada Windows

Results

As you can see each company shows a different order for best ER performing window style - picture windows being the exception.

Making Windows Equally Efficient Through Technology

Energy efficiency in windows is calculated based on several factors, including heat gain, heat loss, and insulation. Manufacturers can enhance these factors through technical adjustments, such as:

• Glazing: Using multiple layers of glass to improve insulation.
• Coatings: Applying low-emissivity (Low-E) coatings to reduce heat transfer.
• Gas Fills: Filling the space between panes with gases like Argon or Krypton to improve insulation.

For example, to improve the efficiency of sliders and hung windows, manufacturers may offer upgrades like replacing Argon with Krypton gas between the panes, which provides better insulation.

Key Takeaways

• Picture Windows: Always a top performer due to their non-operational nature, offering maximum insulation.
• Casement, Awning, and Hopper Windows: Efficient designs that provide good insulation and ventilation.
• Single and Double-Hung Windows: Traditionally less efficient but can be upgraded with better glazing and gas fills.
• Single and Double-Slider Windows: Similar to hung windows in efficiency but can also benefit from technical upgrades.

When choosing new windows, it's crucial to consider not only the style but also the specific technologies and upgrades available. Understanding these factors will help you select windows that offer the best energy efficiency for your home.