Windows and More

For many homes, starting with Steps 1-3 will be the most cost-effective approach to lowering energy bills and keeping indoor temperatures comfortable. This section covers some of the other energy upgrades you can do.



Dual (or even triple) panes provide greater insulating value than single panes, while low-e glass reflects infrared light. Window characteristics to compare include:

  • U-factor – the lower the U-factor, the less heat is transmitted through the window.
  • Solar heat gain coefficient (SHGC) – the lower the SHGC, the lower the solar heat gain.
  • Visible transmittance (VT) – measures how much visible light passes through the glass.

The ENERGY STAR label will help you identify energy-efficient windows.

Tip: Air sealing, duct sealing and insulation may be more cost-effective than a window upgrade. If budget is a concern, start with diagnostic testing on your home to determine which upgrade will give you the biggest “bang for your buck.”

Solar Electric Systems

Once you have reduced the amount of energy your home is using, consider producing the equivalent of your remaining electric load with a solar electric system. A home that produces as much energy as it uses is known as a net zero energy home.