How Window Glass Ratings Affect Replacement Window Performance and Price

December 26, 2009

If you're considering replacement windows, you might be amazed by the features and options from which to choose. However, the name of the game is window ratings. Good ratings can mean energy savings.

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At the same time, good ratings can sometimes mean a higher initial price tag. But you may find that you can recoup those expenses over the long haul by achieving monthly energy savings.

Window Glass Ratings and Energy-Saving Innovations

The Louisiana Department of Natural Resources discusses window glass ratings and reveals several energy-savings extras that could mean a lower monthly energy bill. What's To Lose? Windows are thermal weak spots, sometimes losing 25 percent of the heat in your home through just 1/8 inch of glass.

  • Multiple Glazing. Double and triple-glazed windows increase the heat resistance exponentially--from single-paned at R-1 to triple-paned at R-3.2
  • Low E-glass. Low-e, or low-emittance, glass features a unique coating that improves heat resistance to around R-2.5 to R-3.5
  • Gas-filled. Typically with Argon because it's safe, inexpensive, and readily available; Argon resists heat conduction

Vinyl Window Ratings: Know the Lingo

Much of the information you need to make an informed decision about purchasing replacement windows can be found in the product description. School yourself on the vinyl window ratings presented by eHow.

  • U-Value. The rate of heat loss--the lower the figure, the better for your energy bill
  • Solar Heat Gain Coefficient (SHGC). The rate of heat penetration from the outside--again, the lower, the better
  • Air and Water Infiltration Tests. The amount of air or water passable from outside to inside

In addition to this summary, the National Fenestration Rating Council (NFRC) also offers up-to-date information on the latest in vinyl window ratings that can help you purchase wisely.


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