Windows can add beautiful natural light, ventilation, and style to a home. They can also be a key factor in energy efficiency. If you’re noticing high energy costs each month, it may be time to look into a project that will add long-term value to your home - window replacement.
But where do you start? Glass packages. The glass package in your windows can have a significant impact on their performance. Let’s take a look at some features of one of the most popular choices for homeowners - double pane glass:
- Energy Efficiency
What is double pane glass, exactly?
Also called double glaze, this window option is one of three approaches used to improve the energy performance of windows. Double pane glass windows assemble two layers of glazing separated by a spacer bar and filled with an odorless, non-toxic gas (often Argon or Krypton). The gas in the cavity between the glass acts as an insulator to help reduce heat transfer. A spacer separates the glass to the appropriate distance. It also serves several other functions including providing a gas-tight seal to prevent the loss of gas.
Image from Glass and Glazing Federation (GGF). Window glass is often called glazing.
What are the energy benefits of double pane windows?
Energy cost savings.
Remember, glass can impact energy efficiency more than any other part of a window. With this type of unit, gas acts as an insulator to better regulate the temperature of your home.
How do double pane windows regulate the temperature of the house?
Looking at double pane glass vs single pane, the added barrier of gas helps resist heat flow, block the transfer of cold air, and block heat producing solar rays. The gas traps the winter’s cold air or summer’s warm air and forms a barrier that blocks the temperatures from affecting your home. The insulating properties of double pane windows reduce the need to rely so heavily on your air conditioner or heater because the air inside the home is affected less by outdoor factors. Single pane windows don’t have insulation so if you currently have single pane windows in your home, double pane windows would certainly be a worthwhile upgrade.
There are several formulas used to determine the energy efficiency of a window, one of which is the Solar Heat Gain Coefficient (SHGC). The SHGC measures a window’s ability to block heat producing solar rays on a scale of 0 to 1 (the lower the rating the better). Energy Star has outlined target SHGC ratings for maximum energy efficiency in all four US climate zones:
ENERGY STAR performance criteria by climate zone
To give you an example of how all of this plays out let’s look at Andersen’s A-Series windows. Andersen A-Series dual pane windows have an SHGC of 0.13–0.26 making them among the most energy efficient ENERGY STAR windows for Texas homes. As you shop around for your windows you'll also hear about triple-pane and quadruple-pane glass packages, the more panes of glass in the package the more they will cost and though they may provide more insulation, your home may not need it for optimal performance. Certain glass packages perform better in certain climates. Where we're located in North Texas, the South Central Zone, double pane (dual pane) glass works well and is more affordable than other options.
What will this investment cost?
With extra glass, gas, and sealants to support the frame, double pane glass is costlier than the single pane glass of yesterday. But remember: the increased insulation properties of double pane glass offer you an opportunity to reduce your energy costs and thus pay for themselves.
Consider the cost of Brennan Traditions windows to give you an idea of pricing; these costs don’t include installation or other fees often associated with window replacement projects:
Brennan Traditions single-hung window in white with high-performance double pane glass: $545.
If you replace five single pane units with the above double pane option, ROI for these windows would be about 10 years factoring in the average ENERGY STAR cost savings for the Dallas-Fort Worth area.
Double pane glass with its insulating gas core is a great option for those who want to improve both the look and the function of their home. A window is a sum of its parts, and the glass package is an important consideration when you’re selecting units that will add value to your home.
For your best home window options, check out our product offerings by brand: