How can I tell if a window is energy efficient?

  • · Check the window’s NFRC rating label. Quality replacement windows will have an NFRC label adhered to each new window.
  • · The NFRC (National Fenestration Rating Council) is an independent testing organization that rates the “U-Factor” for replacement windows.
  • · U-Factor is the amount of heat transferred through a material.
  • · The Federal guideline recommendation is .30 or less
  • · Lower U-Factor numbers can be achieved. The lower the U-Factor, the slower the heat flow, the better the insulating quality.
  • · A newer measurement mandated to measure window efficiency is SHGC (Solar Heat Gain Coefficient)
  • · SHGC measures how much heat is allowed to transfer through the glass by the sun’s rays.
  • · The lower the number the better. Typically .30 or less.