Windows are accepted as “Energy Star Qualified” if they meet certain criteria for energy efficiency. cites the following important energy efficient aspects of windows:

  • 1) Improved frame materials:
    Wood composites, vinyl and fiberglass frames reduce heat transfer and help insulate better.
  • 2) Multi-panes: Two to three panes of glass with air of special gas filled space in the middle insulate much better than a single pane. A third pane also adds to sound insulation and impact resistance.

Low E Glass (Low Emittance):

This special type of glass has a coating that reflects infrared light, allowing less heat transfer. An added benefit of this type of glass is that it reflects damaging ultraviolet light, protecting upholstery and curtains from fading. The coating is a thin layer with metal deposits, coating the glazing surface.

Gas Fills:

Energy efficiency in windows can be improved with argon, krypton, or other gases that insulate better than air.

Warm Edge Spacers:

Made from steel, fiberglass, or vinyl, these edges between the glass help prevent condensation and reduce heat flow.