The Efficient Windows Collaborative (EWC) is a consortium of manufacturers, home performance contractors, research organizations and others dedicated to increasing the market share of high-efficiency windows in both the residential and commercial sectors.

The EWC promotes energy performance rating and labeling among window manufacturers and educates builders, designers, and consumers about the benefits of energy-efficient windows and how to select efficient windows for various climates.

The EWC also supports the development of a market for emerging window technologies by providing information about their energy savings potential. It also provides education, research and policy advice to support the use of energy efficient windows and related design decisions.