Understanding High-Performance Windows: What You Need to Know

Hey, everybody! It’s TJ with Sanctified Homes, and today we’re here with Steve from Lindsay Windows at our latest project site, The Bushel Hill Haven. We’re diving deep into what makes high-performance windows essential for energy-efficient, comfortable, and durable homes. Windows may seem simple, but they’re actually complex, with tons of factors influencing how they perform. Let’s break down everything you need to know to make an informed choice.

Why High-Performance Windows Matter

High-performance windows are more than just glass—they are engineered systems that keep homes energy-efficient and comfortable year-round. When selecting windows for a custom home, the right choice can drastically improve your home’s thermal efficiency, reduce noise, and enhance indoor air quality.

We often see people overlook window quality, opting for whatever option their builder or contractor selects. But given how much heat gain and loss occurs through windows, it’s worth understanding the specs that make a high-performance window.

Key Features to Look for in High-Performance Windows

Here are some critical factors you’ll see on any high-performance window label. Let’s break down what they mean and why they matter.

1. U-Factor: Measures Heat Transfer

The U-factor indicates how well a window keeps heat inside. Lower numbers are better because they signify greater insulation and energy efficiency. For our Bushel Hill Haven project, we chose windows with a U-factor of 0.22. To put this into perspective, most standard windows only meet a minimum U-factor standard, meaning these high-performance windows will help lower energy costs and maintain a stable indoor temperature.

2. Solar Heat Gain Coefficient (SHGC): Controls Solar Energy Entry

SHGC measures how much solar energy passes through the window. In warmer climates, a low SHGC is preferred to reduce heat gain, keeping cooling costs down. For colder climates, a slightly higher SHGC might help warm the home during the winter. We generally recommend a lower SHGC since it reduces indoor temperature fluctuations and protects furniture from UV damage.

3. Visible Transmittance (VT): The Amount of Natural Light

Visible transmittance tells you how much natural light passes through the window. Higher VT values mean more natural light, but each layer of coating applied to the glass can lower this number. At 0.46, these windows still allow a good amount of sunlight to pass through without the risk of overheating the space.

4. Air Leakage: Keeping Drafts at Bay

Air leakage is one of the lesser-known but crucial aspects of window performance. It measures how much air (in cubic feet per minute) can leak through a window. Lower numbers mean fewer drafts and better insulation. Our chosen windows test at 0.01 CFM—significantly below the industry standard of 3 CFM. This ultra-low leakage rate is essential for energy efficiency and comfort.

Advanced Window Technology in Action

For this home, we chose Low-E (low emissivity) glass with a 366 neat coating and i89 option. Here’s what that means:

• Low-E 366 Neat Coating: The outer glass layer has a triple-layer Low-E coating to block UV rays, reduce heat gain, and make the glass surface stay cleaner for longer.

• i89 Indium Coating: This inner coating reflects heat back into the home during winter, helping to maintain indoor temperatures and reduce heating costs.

These options mean that not only do these windows reduce heat gain from the outside, but they also help keep indoor warmth from escaping.

How Glass Type Influences Energy Efficiency

Different glass types influence performance. Lindsay Windows provides various glass coatings, like Low-E 180, Low-E 270, Low-E 366, and even a more advanced Low-E 452. These options allow us to customize windows for maximum performance based on the home’s orientation, climate, and your personal preferences.

For instance:

• In a south-facing room where there’s intense sunlight, a higher Low-E coating will reduce the solar heat gain.

• On the north side with minimal sun exposure, a lower Low-E coating may be ideal to allow for more natural warmth during the winter.

Real-World Benefits of High-Performance Windows

So, why does all of this matter? High-performance windows improve comfort and efficiency while lowering energy costs. Here are some specific benefits you’ll enjoy with high-quality, well-sealed windows:

1. Better Indoor Air Quality: With low air leakage rates, pollutants and allergens stay outside, contributing to healthier indoor air.

2. Lower Energy Bills: Efficient windows reduce your reliance on heating and cooling systems, cutting energy costs significantly.

3. Increased Comfort: Properly selected windows reduce drafts and prevent overheating, making for a more consistent indoor environment.

4. Noise Reduction: High-performance windows have superior soundproofing qualities, which is particularly valuable in noisy neighborhoods.

Choosing the Right Windows for Your Build

When selecting windows, remember that it’s about more than aesthetics. Ask your builder or window supplier the following:

• What’s the U-factor and SHGC for these windows?

• Is there an option to customize the Low-E coating based on window placement and sun exposure?

• What’s the air leakage rate?

Properly researching these specs will help you make an informed decision and ensure your home stays comfortable and efficient.

Conclusion

High-performance windows are an investment that pays off in comfort, efficiency, and value. By selecting the right glass type, coatings, and ensuring proper installation, you can significantly enhance your home’s durability and sustainability. Windows may seem simple, but their role in a home’s performance is anything but basic.

If you have questions about high-performance windows or want to explore options for your new build or remodel, feel free to reach out. And, as always, don’t forget to raise your standard! We’ll talk to you soon.