To ensure that your comparisons are valid, you should also ensure that the R values of the different windows are set using the same standards.For even more advice, information and inspiration delivered straight to your door, subscribe to Homebuilding & Renovating magazine. So you should try to get an idea of the R value when all is factored in and make sure that you’re not only being told the R value of the center of the window.
Having triple pane windows using an aluminum frame might not be better than having a dual pane with a fiberglass frame. This means you should take into consideration the frames for each comparison. You should also make sure you are comparing like with like. When you are getting windows, you should check to see what the R values are, so you can compare which ones are more energy efficient. However triple pane windows can go beyond an r value of 5.0. R values for windows generally range from around 0.88 to 3.0.
This means the lower the U value, the better it will be for energy efficiency. So the higher the U value, then the more heat transfer is allowed. The U value of a window is actually the inverse of the R value. Therefore the higher the R value, the better its energy efficiency will be. The R value of a window measures how well it resists heat. Windows are given ratings that indicate how well they resist heat conduction, or how well they conduct heat. For if the window and frame are not tightly fitted to the space where they should go, then air and heat will be transmitted freely through the gaps. A poorly installed window could defeat all your efforts to enhance energy efficiency. Aluminum frames are not as good insulators as wooden and vinyl window frames.ĥ. Some frames conduct heat better than others. The type of frame and spacer materials used. There is also heat-absorbing glass, which can absorb up to 45% of the solar energy.Ĥ. Triple panes allow an extra pane to be treated with a low-e coating, thereby giving it even greater potential for higher energy efficiency. Low emissivity (low-e) glass allows the light to pass through fully, but it reflects 40% to 70% of the heat. There are different types of treatments that can be applied to glass which would impact on the energy efficiency of the window. Filling with an inert gas like argon or potassium will give better resistance to heat transfer, than just filling it with air.ģ. What is used to fill the “air” space will also affect the conductivity of the glass. Going smaller or bigger will reduce the energy efficiency. The width of the air space matters because to get the best efficiency, they should fall between specific sizes. How much air space is allowed between the glass panes. So one would naturally expect that double panes would perform better than single panes, and triple better than double.Ģ. The more layers the window has, the greater the insulation.
In this article, we will look at how to compare the energy efficiency of windows.įirst let us understand the five main factors that determine energy efficiency of windows.ġ. For this reason, double pane and triple pane windows are much preferred over single pane windows. It is not possible to totally prevent heat loss or gain, but it is possible to significantly reduce it by having well insulated windows.
During cold times, like winter, your home will lose heat making it colder inside, which of course you want to avoid, as this will cost you more to keep your home warm. This means that during the warm times such as summer, your home will tend to gain heat through your windows, which is usually undesirable, as it is not only a discomfort, but it will cost you more to keep your home cool. Windows are a major source of heat loss or gain.