How Do Energy Efficient Windows Work?


If you’ve lived in the Phoenix area for very long, you know energy efficiency is a must to prevent you from going bankrupt from air conditioning costs during the long summer months.

And, because we do live in the desert, temps manage to dip low enough during those winter nights to necessitate turning the heater on.

Whether you want to keep the heat in or out, energy efficient windows are your best bet for saving money on energy costs.

So, how exactly do energy efficient windows work? At the core of what makes these windows an ideal investment is advanced engineering and technology that has been developed over the past few years.


Preparing the Window

Energy-efficient windows still use glass, but use a low-emissivity (Low-E) glass, which not only provides a barrier for sun rays, but shields the inside of your house, helping you maintain a consistent temperature.

For example, in the winter, Low-E glass keeps the heat inside and the cold out. In addition to the coating on the glass, many different window manufacturers produce windows with different glazes, tints, or reflective coatings. Each finishing step fulfills a different need and helps you find a unique way to save money and energy.


Window Construction

In multiple-paned windows, manufacturers have found great benefit to using gas fills. The gas helps to reduce the rate of heat transfer between the outside air and inside of your house. In the frame, adding polymer structural foam has become an integral part of an energy-efficient window. Previously, manufacturers often used metal to insulate the windows.

And when you’re ready to purchase, ask about the U-factor or U-value. The U-value shows the window’s resistance to heat and the insulating properties. You want a number that is low—energy-efficient double-paned windows usually have .3. and triple-paned windows might get as low as .15. In a triple-paned window, you’ll get a higher UV blockage rate as well.


XO Windows: Save Money with Energy Efficient Windows

Interested? Call XO Windows. We specialize in energy efficient windows and can help you understand the details behind each option and help you pick the best possible windows for your home. From vinyl and aluminum to off shapes and unique needs, XO Windows can help you find the

Energy Efficient Windows: Keep Your Home Cool This Summer With These Tips

Woman relaxing in chair

Summer temperatures in Arizona can soar into the triple digits. Trying to combat this heat using only air conditioning sends energy bills skyrocketing and puts a serious dent in your budget. AC units that work overtime are also more subject to wear and tear, which can lead to premature breakdowns and unwanted repair costs.

Instead of pouring all of your money into your cooling unit, why not try a few simple methods to keep heat from entering your home in the first place? From adding treatments to existing windows to replacing old windows with updated energy efficient models, these fixes can dramatically reduce your need for air conditioning.

Keep in mind that south- and west-facing windows get the brunt of summer sunlight and will therefore benefit the most from these modifications.

Blinds and Curtains

Installing tight-fitting blinds or insulated curtains lets you shut out the sun before the day gets too hot. Choose curtains with reflective backings to block as much as 33 percent of heat gain. Blinds should slat together as closely as possible to reduce the amount of light that “leaks” into the house. Whether you use blinds or curtains, make sure you shut them before the sun starts to beat down. Otherwise, you’ll end up trapping heat inside and sweating your way through the day.


Shutters are not only a great way to keep your home cool but they can also be an attractive addition to exterior decor. Some have adjustable slats so that you can let in a little bit of light when you want it and block it out completely when you don’t. Installing outdoor shutters also helps to keep your windows safe during severe weather. If you prefer interior shutters, choose a plantation style that can be opened and closed in a way similar to blinds.


Another attractive way to cut down on cooling costs is to install awnings above your south and west windows. According to the US Department of Energy, awnings can block 77 percent of the sun’s heat. Choose colors that coordinate with your home but avoid dark shades since these absorb light instead of reflecting it.


Interior window shades should also be light in color, preferably cream or white. When mounted close to the glass, shades create a “seal” that blocks unwanted light from coming in while preventing cool air from leaking out. Pleated or honeycomb shades help keep things even cooler thanks to insulating air pockets created within the material of the shade. These window treatments are an easy and cost-effective way to keep out 40 to 50 percent of the heat that would otherwise make your home uncomfortable during the blazing Arizona summer.


As long as you choose a tight enough weave, installing exterior screens will keep the sun’s heat from reaching window glass. Screens dim light less than blinds, shutters or drapes while staving off 60 to 80 percent of outdoor heat.


Weather stripping and caulking both sound like chores that only need to be tackled in cold climates. However, the same leaks around windows that let in the cold in wintry areas let it out on hot days. You pay for cooled air whether or not it stays inside, so sealing up leaks is a way not only to keep cool but to save money on energy bills.

Energy Efficient Windows

Perhaps the best way to stay cool and comfortable this summer is replacing your windows with modern energy efficient models, which can also make a world of difference when it comes to cooling costs.

Windows labeled with an Energy Star rating are designed to keep interior temperatures consistent regardless of the current weather. Several elements work together for overall improved window efficiency:

  • “Low-e” glass that reflects the sun’s rays back outside
  • A low solar heat gain coefficient (SHGC), indicating that only a small amount of radiant heat comes through the glass
  • A high U-factor to show resistance to heat flow
  • Double-paned glass with insulating gas such as argon

Energy efficient windows should also have a low rate of air leakage to ensure that heat stays outside while cool air remains in your home.

When choosing any kind of energy-saving window treatment or upgrade, always check the R-value. This number shows the ability of a material to resist heat. The higher the R-value, the less heat will wind up in your home. Though some home cooling methods may seem like significant investments up front, high quality products with low SHGC and high R-value pay for themselves over time with the money you save from not having to run the air conditioning day in and day out.

In addition to these changes, one of the simplest things you can do to keep your home cool is open up the windows in the morning and evening when the outdoor temperature is lower. Starting and ending the day with an infusion of naturally cool air will improve the efficiency of other cooling measures and help prevent your home from getting stuffy.

If you’re ready to upgrade to a more efficient home this summer, XO Windows has a complete line of windows and sunscreens to help you keep cool and save money.