Windows provide light, ventilation and a view of the world. When considering buying or replacing your home windows you can accomplish these three tasks while doing so in a more energy-efficient way. In recent years, windows have undergone several technological advancements and it is now possible to purchase windows that have lower heat loss, less air leakage and reduced solar heat gain to improve overall comfort and style. No single solution is right for every home or every climate. There are many factors for homeowners to consider when purchasing windows.

When considering replacing windows, homeowners should first look for several indicators that their old ones are no longer efficient or effective. Windows should be replaced if they have air leaks in, out or around the window or are difficult to open and close. Windows that no longer open easily or are painted or nailed shut pose a safety risk as they may prevent a safe escape during a house fire. It is recommended that windows are inspected annually as part of regular home maintenance. As needed, windows should be cleaned, repainted and recaulked to maintain performance.

If it is determined that your windows need replacement, deciding to purchase more energy efficient windows can save homeowners hundreds of dollars in heating and cooling costs. To further financially benefit homeowners who increase the energy efficiency of their home, the federal government passed the Energy Policy Act in 2005, which allows homeowners to claim tax credits if they upgrade their homes with qualified windows, doors or skylights. For windows installed in 2006 and 2007, homeowners may receive a deduction of 10 percent of the purchase price up to $200 (not including installation) of qualified components from their income taxes.

To assist homeowners in deciding which windows to purchase, the National Fenestration Rating Council (NFRC) has developed a window rating system to provide a reliable way of determining the energy efficient properties of a window. The label illustrates the windows U-factor, solar heat gain coefficient, visible transmittance and air leakage properties. The lower the U-factor, the greater the window’s resistance to heat flow and the better its insulating value is. The lower a window’s solar heat gain coefficient, the less solar heat it transmits and the higher the visible transmittance the more light is transmitted. A high visible transmittance is desirable to maximize daylight. Air leakage is measured by how much heat loss and gain occur by infiltration through cracks in the window assembly. The lower the air leakage number the less air will pass through the assembly. Of the four values listed on the NFRC label, the two most important factors to consider are the U-value and solar heat gain coefficient. Purchasing windows while following these simple guidelines will assist in saving money on heating and cooling bills compared to those that do not meet these standards.  

Once a homeowner decides to purchase energy efficient windows the next decision to make is which style is most appropriate for the space it is to be installed. Some of the more common types are awning, casement, double hung, and picture. Each have different benefits and operate and function based on their design. An awning window hinges at the top and tilts out at the bottom. They provide ventilation, even during rain, provide ample light and are often installed above doors. Casement windows offer a large viewing area and are hinged on one side. These vertical windows swing out to offer good ventilation and are easy to clean. Double hung windows are the most traditional style window and open by raising the lower half or lowering the upper half. Double hung windows take up less space and are ideal for installing next to patios or porches. Pictures windows provide ample light and a wide viewing area but are fixed and cannot be opened for ventilation. Depending on a homeowners need and taste there is a style designed for all homes.

To further improve the energy efficiency of your home by upgrading your windows, homeowners can keep their home cooler in the summer and warmer in the winter by choosing low emissivity (Low-E) glass coatings. Low-E coatings reduce heat transfer and minimize the amount of UV rays that pass through the glass. Homeowners can also reduce heating and cooling costs by replacing old single pane windows with more efficient double or triple pane windows and regardless of which style window is chosen high quality weather-stripping is essential to maintaining a high level of efficiency.