Reducing the solar heat gain with low SHGC low-E glass can be achieved by installing high performance windows in new homes or in existing homes.

In addition to blocking solar heat, the low-E glass also insulates better than standard glass, so the window U-factor is also improved. The lowest U-factors will occur in windows with low-E glass AND an improved frame material.

The best year round performance comes when windows have low solar heat gain low-E glass and a wood or vinyl frame. Thermally broken aluminum frames are also an improvement on the solid aluminum window frame of old.

Low U-factor windows with improved frame materials will also experience far less condensation than a solid metal frame.