How to Choose the Right Type of Glass for Your Replacement Windows

choosing-right-glass-replacement-windowsIf you’re like many replacement window customers, energy efficiency is high on the list of the benefits you expect to get for your investment. Choosing the right type of glass is one way to maximize the energy efficiency benefits of your replacement window investment.

Fortunately, the ENERGY STAR® program has made it easy for homeowners to select new windows that will help them keep their heating and cooling costs in check. All you have to do is ask whether the replacement windows you’re considering for purchase are ENERGY STAR-certified for the region where you live. If they are, that means they meet the industry’s standards to be considered energy efficient.

As with any other home upgrade, however, the devil is in the details, and no two homes are exactly alike. Therefore, the most energy-efficient windows for one home may not be the ideal choice for another, even in the same region, because factors like which way a window faces can play a role.

What Features Boost the Thermal Performance of Window Glass?

For homeowners who want to go beyond looking for the ENERGY STAR label, it’s helpful to discuss some of the basics of energy-efficient window glass. Here are two of the standard features to look for:

Multi-Pane Glass

Most energy-efficient windows are built with double-pane glass, and triple-pane glass is an optional upgrade. Using more than one pane of glass boosts a window’s insulative performance over that of outdated single-pane windows, but even better is dual-pane glass with gas fill between the panes for enhanced insulation.

Special Glass Coatings to Manage Heat Gain

Low-emissivity (Low-E) coatings are microscopically thin layers of silver and ceramic materials applied to the surface of window glass to control the amount of solar heat and light that can pass through. These coatings are categorized as Low E1, Low E2, and Low E3 to denote which type of climate they are best suited for. For example, Low E1 is often the best choice for homes in the North, where heating costs are more of a concern than cooling costs. On the other hand, homeowners in Cincinnati and other communities in the North Central zone must deal with extreme temperatures in both the winter and summer, and that can drive up the need for year-round indoor climate control. Window glass with Low E2 coatings is typically their best choice.

What Do Window Glass Ratings Mean?

Replacement window glass is rated according to three primary criteria:


This is a measurement of how well a window keeps heat inside your home, so it’s of utmost importance to homeowners who are concerned about their heating bills. The lower the number, the better the insulation performance. In the Cincinnati area, the U-factor should be 0.32 or less.

Solar Heat Gain Coefficient (SHGC)

The SHGC measures how much radiant heat enters your home—typically a top concern for homeowners in Southern climates. North Central homeowners should look for an SHGC rating of 0.40 or less.

Visible Transmittance

This is a measure of how clear a window’s Low-E glass is. The higher the visible transmittance number, the clearer the glass. The goal is to allow plenty of sunlight to enter a home while protecting upholstery, drapes, and carpet from fading. A good visible transmittance score is between 0.5 and 0.7.

Of course, if you’re planning to replace your windows, you may want to explore options for decorative and privacy glass, as well as glass that can reduce the amount of outside noise that invades your home.

If you’re in the Cincinnati area, the window experts at Holmes Custom Renovations will be delighted to arrange a free consultation to discuss your window replacement options. We proudly offer and install windows manufactured by Infinity® from Marvin, a brand that’s known for high-quality craftsmanship as well as a generous array of customization options.

When you partner with Holmes Custom Renovations, we’ll take the time to help you choose just the right glass and other customization features to create the ideal windows for your home. Contact us today to get started.