Window Styles by Type
- Single- and double-hung window are the most common, with the former having only one sash, the bottom, that slides vertically. With the double-hung style, each window moves. According to the U.S. Department of Energy, these types of windows allow more air leakage than other types.
- Single- and double-sliding windows work similarly to the above, but with the windows sliding horizontally. They present the same air loss problem.
- Awning windows have hinges at the top, and they open outward. The sash closes tightly against the frame, which offers higher energy efficiency.
- Casement windows have hinges on each side, and they open outward. Because the sash also closes tightly against the frame, they prevent more air from leaking in or out as well.
- Hopper windows have hinges at the bottom and open inward. They function as awning and casement windows do, offering higher energy efficiency.
- Fixed pane windows are exactly that: They do not open and, therefore, do not allowair in or out. These may be suitable for applications which you want to let light in but will never require air circulation, such as decorative elements higher up in a room or stairway.
Types of Window Frame Materials
- Metal frames are typically made of aluminum, and though strong and light they conduct heat and lower the energy efficiency of a window, according to the U.S. Department of Energy.
- Wood frames offer more insulation from the environment outside, but those weather elements cause expanding and contracting that results in inconsistency in energy efficiency.
- Composite frames offer the same level of insulation but without the instability, and they also resist moisture and decay better.
- Fiberglass and vinyl both offer better energy efficiency than the previously mentioned materials because their air cavities can be filled with insulation. They also do not decay as wood does.
Window Glass and Coating Options
- With respect to insulation, windows labeled as featuring same have two or more panes of glass. The panes are hermetically sealed and can be filled with an inert gas such as argon or krypton to improve resistance to heat flow than that of air alone.
- Tinting can also absorb solar radiation, but choose the color of tinting based on your climate to ensure it does not absorb more light than you would like. For example, gray and bronze reduce the amount of heat and light that get in, while blue and green allow in more light than heat.
- Reflective coatings are available in silver, gold and bronze, among others, and do what their name implies: reflect solar heat away from the home.
- Low-emissivity coatings also are available and can reduce energy loss by as much as 50 percent, according to the U.S. Department of Energy. You will pay for those savings, though, because the purchase price is higher for these windows.
There are also custom applications that combine as many of these elements as you need to suit your home and its environment. While more advanced DIYers can replace their own windows, the specialty tinting and coating are best left to professionals. This method will ensure that you are achieving the proper combination of tools to improve the energy efficiency of your home without offsetting it by having to increase the wattage of your lighting inside.The U.S. Department of Energy website can help you determine energy efficiency ratings of any products you purchase for your home.