Energy Ratings For Window Replacement

Energy Ratings For Window Replacement

Window replacement is usually not a choice people like to make. They look at the upfront costs and find that the time it will take to recoup that cost will take, on average, thirteen years. What isn’t figured into to this equation is the increase in home value, the increase in immediate enjoyment and comfort, and, if using energy efficient casements, that the energy being used is being optimized.

Another benefit to look into is tax credits from either your state or federal government or both. Items like solar water heaters, additional insulation, and energy efficient products, are often subsidized by government. Rebates from manufacturers and in house sales at retail stores can save even more money. With good planning, the replacement cost of glazing (glass) products can be decreased between ten to forty percent.

The National Fenestration Rating Council or NFRC is a non-profit organization created by the door, window, and skylight industry. All of these products are rated by taking into account the efficiency and effectiveness of the whole product. Understanding how to read these energy performance ratings will assure you are getting the most efficiency you can afford.

Five characteristics of the window are rated for performance. These are classified as follows: condensation resistance, air leakage, visible transmittance, solar heat gain coefficient and the U-factor. These same ratings are used for doors and skylights.

The U-factor measures the rate of heat loss of an assembled product. The rating measures the insulating properties of the frame, spacers, and glazing (glass). U-factor values can range from. 15 to 1.25. When the factor is considered low (less than 0.30), it means the widow is better insulated. Increased insulation keeps the inside temperature in and the outside temperature out.

SHGC or Solar Heat Gain Coefficient rates how well the assembly blocks the suns heat. This scale is from zero to one with common readings of 0.25 to 0.80. Lower means better in the case of SHGC. A rating close to zero means the solar radiation transmitted through the glass and absorbed by the product materials is more successfully blocked. The free heat from southern exposure in the winter is usually wanted. When choosing windows for this orientation a higher SHGC may make more sense.

Visible Transmittance (VT) refers to the amount of light allowed through the window. The scale, again, is zero to one and the higher the number represents the amount of light and view allowed into the interior. Normal ranges are 0.30 to 0.80.

AL or air leakage reporting is optional at this time. This rating measures the amount of air that leaks out of a square foot of window space. Look for a rate of less than 0.30.

Condensation resistance (CR) speaks to how well the product prohibits the formation of condensation on the interior of the window. This rating is also optional at this time. The scale is from one to one hundred with a higher number equating to better protection.

Many rebates or government credits require a specific rating to be met for the U-factor and the SHGC in order to qualify. All of this information should be available to you at time of purchase. If you didn’t get this information, search the product online and make sure it will meet the qualifications.