Do you have eco friendly windows? Whether you’re in the market for new windows or you have older ones, there are a lot of things you can do to make sure that your windows are easy on the environment. It doesn’t have to cost a lot either.
The connection between windows and the environment is their ability to retain heat in winter and keep it out in summer. The most energy efficient windows will save you tons of money in reduced air conditioning and heating costs. And of course, a secondary effect is that lower energy usage equates to fewer fossil fuel emissions.
Here are four tips for making sure you have the most eco friendly windows possible.
1) Mind your U’s and Coefficients. There are two primary measures of window energy efficiency. If you’re in the market for new windows, look for a window’s U-factor and Solar Heat Gain Coefficient.
The U-factor, usually a value between 0.20 and 1.20, is a measure of how well a window prevents heat from leaving your home. The formula for it is arcane, but the result is some decimal value. The lower the number, the better–meaning that the lower the number, the better the window keeps heat in, which is of particular value during the winter season especially in Northern climates.
The solar heat gain coefficient (SHGC), a value between 0 and 1, is a measure of how well the window blocks heat from sunlight. The lower the number, the better the window blocks unwanted heat. Whether you want a lower or higher number depends on where you live–in Northern climates you want more heat in your home during winter so a higher value is better (the window blocks less heat), whereas in southern climates you’d want the opposite and therefore a lower value.
If this is all a bit confusing, simply look for the Energy Star label on any windows you buy (in the US). The label is keyed to, and will have the proper values for, your local climate, so that you can be sure that you are buying the best type of window for your location.
The best energy efficient windows often have krypton or argon gas in between multiple (2 or 3) panes of glass, which provide even greater insulating value. Marketing materials may also trumpet other supposedly energy efficient attributes. This can all translate to greater expense, however, and may not always be necessary depending on your local climate needs. So don’t assume that the most expensive window is necessarily the best one–again, the Energy Star (or equivalent) label is the friend of the smart shopper.
2) Caulk and seal. If you’re looking to make existing windows more eco friendly and energy efficient, then obviously U-factor and SHGC aren’t going to be as important. Instead, attend to common sense repairs like caulking, sealing, and weatherstripping. If you put your hand around the window you might be amazed where you might feel drafts, especially on a cold winter day. That draft is equivalent to money streaming out of your pocket and wasteful fossil fuel being burned (in the form of home heating).
Stop the bleeding. It is very easy and inexpensive to install weatherstripping and caulking around windows that need it. Replace caulking that is cracked and old. If there is air leakage in between double-hung windows, a foam strip will mostly fix the problem (although it may look a bit unsightly.)
3) Install storm windows. Don’t want to get rid of your old windows? Maybe they have historic or sentimental value, or maybe you’re on a tight budget that prevents you from replacing all of your old windows. That’s fine. Eco friendly windows can be storm windows that you install either on the inside or outside of your existing windows.
While this solution is not ideal compared to energy efficient glass windows, studies have shown that storm windows do reduce air movement into and out of older windows. As such, they greatly reduce the amount of drafts, and therefore reduce your cooling and heating expenses.
4) Window coverings matter. Whether it’s the heat of summer or the cold of winter, the right curtains can make a big difference in reducing your energy bills. They won’t do much of anything to stop drafts, but they play a big part in managing the solar energy that comes into and leaves your house.
Take blinds, for example. They won’t do much to stop winter heat loss, but they’re great for keeping the hot sun out in summer. Highly reflective blinds can reduce the heat coming into your house by half or more.
Drapes are trickier, because factors from fabric type to color will all influence their effect on energy transferrence. Generally, closing the curtains in summer will reduce heat to some extent. One University of Florida study found that medium colored drapes with white backings reduce heat gain by 33%. In winter, they reduce heat loss through the window, so keeping them shut then makes sense too. They work best when they are hung close to the window and allowed to fall to the window sill or the floor.
Whether you go the route of full replacement or incremental fixes, you can easily have eco friendly windows that save you money and spare the environment the costs of excess heating and cooling.
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