What Makes a Window Energy Efficient?
With rising energy prices and harsher winters and summers in the future, everyone is in a hurry to figure out how to solve these many crises as they stack up in and out of their own homes. One place where most homes suffer in terms of energy efficiency is windows. A window is a great way to get natural light and a view but can make the rest of the home suffer from outside elements if it’s not in good shape. Here are the things to look for in windows with high energy efficiency, whether you have them and want to upgrade, or are looking into the best options for a new installation:
Multiple Window Glass Panes
Glass is normally a very neutral material, which is why it’s used in chemistry. Most liquids or solids don’t interact with glass. But glass is a conductor for temperature. Glass gets, and stays, hot or cold depending on its surroundings. This means a window with just one pane of glass will be whatever is the strongest temperature, usually from the outside. Having multiple panes (most windows are two or three-pane by default) means the glass on the outside won’t affect the glass on the inside nearly as much. Other materials like plastic or other glass alternatives have their own setbacks, mostly in the energy efficiency department. They may seem cheaper upfront, but the cost of heating and cooling used up over the year will offset that discount. Glass is worth the higher price because of the energy efficiency it guarantees.
Quality Window Frame Materials
The frame is what keeps the glass in place and connects the window to the surrounding wall or fixture. A perfect glass seal on a window doesn’t mean much if the hole is cut to the wrong size or filled in with sub-par material. The window frame can contribute to energy efficiency by insulating the surroundings so that the outside temperatures don’t get in, or produce leaks. You may want to keep things consistent with a wood or fiberglass frame, but vinyl has much more insulation and aluminum is highly durable keeping it low maintenance but generally inefficient as metal is a high conductor for external temperatures. Wood is generally seen to be the most energy efficient, and the most stylish if combined with a natural wood-siding from the outside.
Low-E Glass Coatings
Glass by itself can be fragile, and in terms of energy efficiency it can be very “leaky”. A window in the winter can be far colder than you expect, and that cold spreads. That is why windows are often treated, usually with a coating, that does not affect their transparency while still reducing spreading temperatures. A Low-E (which stands for Low Emissivity) coating heps reflect infrared and ultraviolet light, which helps keep out heat and glare from the sun. It also prevents sun damage on furniture or walls where the sun hits through the glass. You get an uninterrupted view of the outdoors without the fear of blinding light or summer heat seeping in.
Window Gas Fills
When multiple window panes are used, they aren’t just stacked up next to each other. Having multiple panes can slow the transmission of temperature, but it won’t stop fully. Space is left between panes and then filled with an unobtrusive gas. Gas fills help regulate the temperature. The layer of air acts as an additional “screen” which absorbs heat or cold before it touches the next pane. These are non-toxic, naturally occurring gasses which insulate better than the regular air they are pulled from. Argon is the most common window gas fill. It’s heavier than regular air, which means it’s harder to change the temperature up or down.
Window spacers are the parts that separate the glass panes from one another and act as a seal for the gas fill inside. They keep out moisture from the outside, so the foggy morning air doesn’t turn your house into a dark and misty, soaking-wet environment. They are also made of specific material which allows for expansion and contraction. Your window may be solid, but temperature causes everything to shrink or expand just a little bit. Without proper support, the glass panes may expand and press too hard against the frame, or contract and open up space to let the air - and elements - through. Window spacers can be made of metal like stainless steel, or composites like silicone foam or aluminum with a hard polyurethane sealant. A good window sealer that matches your environment will keep your window efficient for much longer, prevent leaks and stop breaks.
Efficiency Windows Benefit Some Homes More Than Others
When people talk about the energy efficiency of their windows, it depends on the climate they live in. Some homes are built for certain environments, and the climate may have changed since they were last modified. Winters get colder, summers get hotter, and springs can get wetter; the same old window that was good enough twenty years ago may not be as efficient as when it was installed. Homes that are located in places where the shift between seasons is extreme need windows that can handle both keeping out the heat for summer and keeping it out in the winter. The more heat invades in the summer, the harder the AC has to act. The more heat escapes in the winter, the more the heating needs to be used. It’s mostly related to heat: hot air is lighter than cold air, and will always seek a means to escape by rising. You can prevent much of that rise if you seal off the walls, which is what energy-efficient windows help to do.