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Energy Star Window Ratings Explained

If you’ve ever shopped for appliances, you’ve undoubtedly seen the ENERGY STAR label pinned to product tags. ENERGY STAR is clearly a selling point. However, you may have wondered exactly what the rating was telling you.

First, you should know that ENERGY STAR isn’t just a metric for appliances that consume energy. It’s also used to rate how “passive” products conserve energy. That’s important if you’re in the process of buying some replacement windows.

You should also know that a good rating isn’t universal. A window rated for New York isn’t going to transfer over the Austin. Simply seeing the ENERGY STAR logo isn’t enough to ensure that a product is a good fit for your specific home.

Take a look at the basics of ENERGY STAR window ratings.
High Performance with ENERGY STAR

What Is the ENERGY STAR Program?

ENERGY STAR is a government program created by the Environmental Protection Agency (EPA) and the Department of Energy (DOE) in 2011 with the purpose of making it easier for consumers to purchase efficient, eco-friendly products that help them to save money while protecting the environment.

The ENERGY STAR Qualifications for Windows

First, only windows that are manufactured by ENERGY STAR partners can receive the ENERGY STAR distinction.

All window products with the ENERGY STAR label have undergone independent testing, certification and verification by the National Fenestration Rating Council (NFRC) that specifically oversees efficiency certification and labeling program for windows, doors and skylights. A 5013 organization, the NFRC uses ratings based on the EPA’s strict efficiency guidelines.

Window Performance for ENERGY STAR

ENERGY STAR ratings vary by climate region. The reason for this is that different products perform differently under different conditions. Some windows are very effective at sealing a home in a way that keeps indoor environments warm. Others are better at preserving coolness in an environment.

When purchasing windows for a home in Texas, the emphasis is obviously going to be on windows that are better at keeping homes cool.

What Is the ENERGY STAR Efficiency Recommendation for Texas Windows?

ENERGY STAR Performance Climate Zones

When looking at ENERGY STAR ratings graphs, focus on the South and South Central zones. The recommendation for efficiency for windows in Texas is a product with no more than 0.35 U-Factor and 0.25 Solar Heat Gain Coefficient (SHGC).

The U-Factor measures how well a product prevents heat from escaping from the inside of your home. The range is 0.20–1.20. Lower numbers preserve heat better.

SHGC measures how well a product resists unwanted heat gain. For Texas, this is important during the summer “cooling” season. SHGC range is 0 to 1. Look for the lowest number possible to avoid watching your energy go out the window.

Tips for Purchasing Efficient Windows

The EPA has some tips if you’re looking at ENERGY STAR window ratings while shopping around. Here’s a look at the qualities that create truly energy-efficient windows:

  • Multiple Panes: Double pane with a gas-filled panel is better than single pane.
  • Quality Frame Materials: Durable, low-maintenance materials that reduce heat transfer are recommended.
  • Low-E Glass: This special coating that reflects infrared light helps to keep homes cooler. The bonus is that it also blocks damaging UV light that fades carpets, furniture and floors.
  • Gas Fills: Some window styles contain a special gas in the center as a “fill.” Odorless, colorless and nontoxic window gasses are great for reducing a window’s efficiency without actually adding any bulk or complex features to a window.
  • Warm Edge Spacers: Spacers keep window panes the correct distance apart to insulate panes while reducing heat transfer through the window.

The EPA also has a lot to say about framing materials! The agency points out that certain framing materials are better than others.

ENERGY STAR windows actually come with a wide variety of framing materials. That gives you lots of freedom when it comes to choosing a style that fits your practical and aesthetic preferences.

Framing Materials Make a Difference

Here’s a look at the top recommendations from the EPA when it comes to selecting framing materials to go with your new ENERGY STAR windows:

  • Fiberglass: Known for being strong and durable with great insulation, fiberglass frames don’t require much maintenance. You’ll find both hollow and foam-filled fiberglass frames.
  • Vinyl: A low-maintenance option, vinyl provides great insulation. You’ll find both hollow and foam-filled vinyl frames. Wider vinyl frames used for covering larger windows are often reinforced with wood or metal.
  • Aluminum: Durable and dependable, aluminum gains bonus points for being recyclable. What’s more, around 15 percent of all aluminum frames are actually made from recycled content. This is a very low-maintenance option that offers great performance. The design of an aluminum frame actually includes special “thermal breaks” that reduce conductive heat loss in your windows.
  • Wood: Strong and attractive, wood is a great option if you’re preserving the look of your historical home. This option provides very good insulation. In addition, wood windows are often covered with vinyl or aluminum surfacing to cut down on the amount of maintenance needed.
  • Combination: Some frames are made of several different materials woven throughout the frame and sash. This goes along with the idea of covering wood windows with vinyl for better preservation and maintenance. However, different combinations can be used.
  • Composite: Composite frames are made from a blend of materials that are combined during manufacturing to create one cohesive solid. This is a great way to get ultra-durable, ultra-insulated frames that are very easy to maintain because they are engineered to offer the best of each framing option.

Yes, it can seem overwhelming to try to decide between all of these options. However, the process is fairly simple once you dive in to begin looking at windows that work with your specific property. A brief conversation with a window pro should actually get you right on track with narrowing down the choices that are best for your home.

Keep in mind that ENERGY STAR windows are produced for all different types of windows for homes. That includes large windows, bay windows, awning windows, bow windows and more!

Let ENERGY STAR Window Ratings Be Your Guides!

If you’re gearing up to shop for replacement windows for your home, ENERGY STAR ratings are amazing resources for really getting to the heart of how each window performs. You’re going to be able to eliminate all of the windows that won’t make your home more efficient right off the bat simply by sticking to the ratings for the South and South Central regions.