When people think about energy efficiency in their home, certain things come to mind. Switching light bulbs to LED from incandescent. Using a smart thermostat to regulate internal temperature. Upgrading the insulation in the walls and attic. Even just turning the lights off when you leave a room. These are all things a homeowner can do to use energy more efficiently.
Yet one thing that not as many people do is replace old windows. In most cases, people don’t fix windows unless they are broken. They have a reason to hesitate: professional window replacement can cost upwards of $1,000. This is because windows are the last line of defense a home has against things like water damage. Even small holes can let bugs, rainwater, or worse in. It pays to have your window done right the first time.
When replacing a window, there are 2 main components to consider: the frame and the pane. Frames hold the pane (sheet of glass) in place within a wall. They can be made of all sorts of materials, from wood to metal to composites. The favored material among window installation experts is new construction vinyl. Vinyl is low maintenance and affordable. It resists moisture and won’t conduct heat. These qualities make it a great choice for homeowners looking to maximize their energy efficiency.
The panes of windows are almost always glass. That doesn’t vary. What can change, however, is how many panes a window supports. Windows with 2 panes are up to 31% more energy efficient than those with just 1. For those serious about energy efficiency, triple pane windows are 48% more energy efficient than single.
Why is this the case? The reason isn’t the glass itself, but rather the space between the glass. Additional window panes create an insulated air space that slows the transfer of heat and sound from inside to outside. The gas between window panes is most commonly an inert gas like argon. This is because argon is common and affordable as a fill gas. It works well in all dimensions of pane spacing. In triple pane units, krypton gas could also be used, but it is much more costly.
Also contributing to the insulating effect of multi-pane windows are the spacers. Spacers help hold the panes in place a certain distance away from one another. Non-metallic spacers are the best. They block heat and cold transfer, reduce condensation, and rarely crack in the seal.
For those who want to get extra energy efficiency out of their windows, coatings on the glass are also available in certain regions of the country. While coated glass costs up to 15% more than clear glass, it can reduce energy loss through windows by up to 50%. In hot and sunny climates, these coatings reduce up to 70% of solar heat gain. They filter out harmful UV rays and infrared light during the summer. Then in winter, they reflect heat from the furnace back into the house. Imagine the energy savings!