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Buying and Installing the Right Product

Every ENERGY STAR qualified 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.

Purchasing Tips

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.

  1. Determine your ENERGY STAR Climate Zone.
  2. Find a retailer or manufacturer. Find a manufacturer or retailer of ENERGY STAR qualified windows, doors, or skylights.
  3. Look for the ENERGY STAR label for your climate zone. All ENERGY STAR qualified products must display the ENERGY STAR label. Check the label to make sure the product you are considering qualifies in your area. The ENERGY STAR label appears on the product next to the National Fenestration Rating Council (NFRC) label:

    ENERGY STAR Qualified
    in Highlighted Regions

    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 windows@energystar.gov.

    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 windows@energystar.gov. 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

    Official ENERGY STAR label (and NFRC Label) for a window qualifying in the Northern, North-Central, and South-Central climate zones.

    ENERGY STAR Qualified
    in All 50 States

    This image shows an ENERGY STAR product qualification label for windows. The product label states “ENERGY STAR Qualified in All 50 States” at the top and has an ENERGY STAR certification mark on the left. On the right is a map of the United States which is completely highlighted to show that the product qualifies throughout the United States. Below the ENEGY STAR label is an example National Fenestration Rating Council (NFRC) Label.

    This image shows an ENERGY STAR product qualification label for windows. The product label states “ENERGY STAR Qualified in All 50 States” at the top and has an ENERGY STAR certification mark on the left. On the right is a map of the United States which is completely highlighted to show that the product qualifies throughout the United States. 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 (0.27 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

    One of the official ENERGY STAR labels (and the NFRC Label) for a window qualifying in all four climate zones (Northern, North-Central, South-Central, and Southern).
  4. Ask for ENERGY STAR when ordering. When you’re ordering in a showroom, make sure to ask for a product that qualifies for ENERGY STAR in your climate zone. You can choose ENERGY STAR qualified windows in a variety of framing materials to suit your needs.
  5. Get a deal. In addition to the long-term energy savings you’ll enjoy, take advantage of financial incentives that lower your initial investment:

    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 qualified windows may cost more than non-qualified 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.

Installing for Efficiency

Proper Installation

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:

  • Stick to manufacturer instructions. Some manufacturers will void your warranty if you do not follow manufacturer installation instructions.
  • Seek out trained professionals. Ask about certification from InstallationMasters, the American Window & Door Institute, or equivalent manufacturer’s certification program. Some warranties require that you use an installer certified by the manufacturer.
  • Evaluate installers. When hiring a contractor, interview candidates and ask for references. The Federal Trade Commission Exit ENERGY STAR Consumer Protection Web site offers home improvement advice under Consumer Information; just click “Shopping for Products & Services.”

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 Exit ENERGY STAR PDF (3.25 MB).

Other Tips

Window Orientation

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 Exit ENERGY STAR.

Source: U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy: A Consumer’s Guide to Energy Efficiency and Renewable Energy, 2005.

Natural, Seasonal Shading

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 Exit ENERGY STAR.

Air Leaks

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.

Condensation

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 qualified 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:

  1. Make sure the space between the window frame and rough opening is insulated during installation.
  2. Choose window treatments that allow air flow over the window surface.
  3. Manage indoor humidity. Vent dryers directly outside. Make sure kitchen and bath fans vent directly outside. Use fans during showers or when cooking, and leave them running for 20 minutes after you’re done.

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.