Windows account for 8 percent to 10 percent of the cost of a new house, according to This Old House. Whether you're looking for the windows to keep your home cool and comfortable, let the air in or minimize maintenance, choosing the right windows for your needs will help you make make the most of your money.
Windows represent a large portion of the building envelope on the average home, so choosing energy-efficient windows can help lower energy bills and keep the home more comfortable. To understand thermal resistance, compare the U-factor of various window models. The lower the U-factor, the better the window is at keeping heat inside, while higher U-factors mean reduced energy efficiency. The U.S. Department of Energy suggests maximizing efficiency by choosing windows with a U-factor of 0.35 or lower. Boost comfort and efficiency even more by selecting windows with special low-emissivity coatings, which can reduce heat transfer by 30 percent to 50 percent, according to the DOE.
A window's solar heat gain coefficient reveals how much heat energy from the sun gets absorbed through the glass. The lower the SHGC, the better the window is at blocking the sun. Windows with more panes of glass and special coatings tend to have lower SHGC values, while those with fewer panes generally have higher SHGC values. If you live in a cold climate zone, pick the highest SHGC you can to maximize warmth from the sun. Choose windows rated at 0.6 or higher for south-facing openings, suggests the DOE. If you live in warmer climates zones like the Southwest, pick windows with lower SHGC values to keep the heat of the sun out of your home.
If you use your windows to bring fresh air into your home and expel stale air, your choice of window design can have a significant impact on ventilation. The DOE suggests casement windows as the best option for home ventilation, followed closely by awning-style windows. Single- and double-hung as well as sliders and hoppers provide roughly half the ventilation capability of casement windows.
The type of frame you choose for your windows can have a major impact on maintenance. Fiberglass, composite and vinyl windows all require little maintenance, making them top choices for those looking to lighten their workload. While aluminum is another low-maintenance option, this material is a notoriously poor insulator and an excellent conductor of heat, making it a poor choice for energy efficiency. Wood windows provide effective insulation but require a great deal of maintenance, including regular staining or repainting.