Most locations have building energy codes that mandate minimum performance levels for windows, doors, and skylights. The builder, contractor or homeowner must adhere to the code requirements, which typically cover windows for new construction as well as replacement windows. These requirements depend on the specific jurisdiction's building energy code. Building energy codes are set at the state or municipal level but are often based on model energy codes.
Energy Rating and Performance Programs
The adoption of energy-efficient windows in new construction has mainly been driven by mandatory building energy codes. In recent years voluntary programs and various sustainable design programs have gained increasing traction as well. Criteria for window energy performance differ among a variety of state and local codes and different voluntary programs. The Building Codes Assistance Project (BCAP) maintains a good list of "beyond code" programs. A few such programs are listed below.