Windows Glass Performance Chart

ALL Four Seasons Energy-Saving Windows and Doors are ENERGY STAR qualified in all zones.

Four Seasons is proud of the outstanding performance of our Energy-Saving Windows and Doors and is pleased to present you with the independently verified performance characteristics of each style for your review. These values are based upon National Fenestration Ratings Council (NFRC) standards for whole product performance (not Center of Glass performance) for a fixed set of environmental conditions and a specific product size.

The chart below lists the ENERGY STAR compliance, the number of panes (double or triple) the gas fill (Argon or Krypton) and the numeric performance values for Visible Transmittance (your view through the glass), Solar Heat Gain Coefficient (how well the glass blocks solar heat from entering your home – the lower the number, the more heat is blocked and the lower your warm weather cooling costs) and the U-Value (how the glass insulates against cold weather – the lower the number, the more insulation value and the lower your cold weather heating costs).

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