Every ENERGY STAR window, door and skylight is independently certified to perform at levels that meet or exceed energy efficiency guidelines set by the U.S. Department of Energy. But how do you know which windows work in your climate or how to install them to maximize your energy savings? The following tips will help you buy with confidence and install for efficiency.
Shopping for new windows, doors, and skylights can be a confusing process. ENERGY STAR makes it simple! Follow these five steps to ensure your windows, doors, and skylights deliver savings and comfort you’ll enjoy.
This image shows an ENERGY STAR product qualification label for windows. The product label states “ENERGY STAR Qualified in Highlighted Regions” at the top and has an ENERGY STAR certification mark on the left. On the right is a map of the United States with the Northern, North-Central, and South-Central Zones highlighted to show where this product qualifies. To learn more about ENERGY STAR climate zones, please contact ENERGY STAR for Windows, Doors, and Skylights at firstname.lastname@example.org. Below the ENEGY STAR label is an example National Fenestration Rating Council (NFRC) Label. The NFRC label lists the company name, the product description, and has the NFRC logo on the left. Below the ENEGY STAR label is an example National Fenestration Rating Council (NFRC) Label. The NFRC label lists the company name, the product description, and has the NFRC logo on the left. Below this are the energy performance ratings, starting with U-factor on the left (0.30 for this window) and Solar Heat Gain Coefficient on the right (0.30 for this window). Below this are the additional performance ratings for this product, which include Visible Transmittance and Air Leakage, neither of which are required for ENERGY STAR qualification. At the very bottom of the NFRC label is the following: Manufacturer stipulates that these ratings conform to applicable NFRC procedures for determining who product performance. NFRC ratings are determined for a fixed set of environmental conditions and a specific product size. Consult manufacturer�s literature for other product performance information. www.nfrc.org
Keep in mind that the cost of complete window replacement for the average home is $7,500-$10,000.* When you’re interviewing contractors, ask them to break down the price quote by labor and materials. ENERGY STAR certified windows, doors, and skylights may cost more than non-certified products, but the labor involved should be comparable for both.
* Based on Consumer Checkbook’s (June 2008) reported average product and installation cost for standard size, double-pane, vinyl, double-hung replacement windows with low-E, grids, and argon fill.
Even the best windows, doors, and skylights can be drafty if they are poorly installed. Here are a few steps to get the most out of your windows, doors, and skylights:
Protect your family from lead. If your house was built before 1978, it probably contains lead-based paint. You should have it inspected by a lead professional to know for certain where the lead-based paint is. Lead dust from lead-based paint is the leading cause of lead poisoning in children. Under new EPA rules, any contractor or landlord replacing a window must use lead-safe work practices to prevent lead dust hazards. All landlords and contractors must provide a brochure to homeowners before beginning a window, door, or skylight replacement. If you’re doing the work yourself, be sure to also follow the lead safety guidelines featured in this brochure (3.25 MB).
Did you know that you can enhance your energy savings even further by selecting specific windows for the different sides of your house?
In colder climates, the ideal window for a South-facing wall has a higher solar heat gain coefficient (SHGC) and a low U-factor to reduce heat loss. Windows that face East and West should have a low SHGC or be shaded. This is especially true for West-facing windows, since they get hit by summer sun at the warmest part of the day. North-facing windows don’t get much direct sun, so SHGC is less important. Instead, buy the lowest U-factor you can afford to minimize heat loss through these North-facing windows.
In warmer climates, you don’t want extra heat from the sun, so a low SHGC is important for windows that face South, East, and West. In hot climates, it is particularly effective to generously shade South-facing windows. As in colder climates, SHGC is less important in North-facing windows since they don’t get much direct sun. It is important to choose a low U-factor for all windows in warmer climates: in addition to minimizing heat loss, low U-factors also reduce your need for cooling.
When building a new home or planning a major addition, consider this: shade in the summer and solar heat gain in the winter can significantly reduce a home’s energy use. Work with the seasons by orienting windows to the South and properly sizing roof overhangs. Keep West-facing windows to a minimum to prevent overheating of those rooms when the sun dips below roof overhangs in the late afternoon. Learn more about designing the home to take advantage of the sun .
Source: U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy: A Consumer’s Guide to Energy Efficiency and Renewable Energy, 2005.
Deciduous trees (those that lose their leaves in autumn) provide shade in the summer when planted near South, East, and West-facing windows, and also let in the sun’s heat during the winter. Learn more about planning a landscape that reduces energy bills .
Air can leak in or out of your house around windows, doors, skylights, and other openings. If you add up all of the hidden air leaks in your home, they can equal a hole the size of an open window! To maximize home efficiency, seal all the gaps where air can leak in or out, including around windows, doors, skylights, wiring holes, recessed lights, plumbing vents, and attic hatches. Stopping drafts can make you more comfortable and reduce energy bills.
Water condenses on interior window surfaces when the surface temperature of the window is below the dew point of the humid indoor air. ENERGY STAR certified windows are more resistant to condensation, but even they can suffer from it in cold weather. To minimize your risk of window condensation, take the following steps:
Exterior condensation can form in warm weather. On a hot, humid day, cool air inside your house can cause the temperature of the outside surface of the window to drop below the dew point, which leads to condensation.