The National Fenestration Rating Council (NFRC), which establishes objective window, door, and skylight energy performance ratings, has acquired the Efficient Windows Collaborative (EWC) and its proprietary online Window Selection Tool.   

As the science behind ENERGY STAR certification for fenestration products, NFRC rates and certifies the energy efficiency of windows, doors, and skylights that make buildings more comfortable and reduce carbon emissions. At the same time, the EWC has been an online resource for consumers to find the high-performance windows specific to their needs. Now, as one well-respected organization becomes a part of another, together NFRC and the EWC will bring a new level of expertise, education, and support to consumers searching for windows for their homes and businesses backed by fair, accurate, and credible ratings.

“This is an incredible opportunity to link the valuable resources of the EWC with those of NFRC to benefit consumers who want the confidence that they are purchasing the right window for their needs,” said Deb Callahan, CEO of NFRC. “This also links the entire fenestration industry with the emerging green building and sustainable industries. The green building market is anticipated to be among the fastest growing industries worldwide. There are great things to come as we expand upon the success of the EWC to highlight the environmental benefit, comfort, and value of energy-efficient windows, doors, and skylights for all consumers.” 

Formed in 1996, the EWC began with funding from the U.S. Department of Energy to work with the University of Minnesota, Alliance to Save Energy, and Lawrence Berkeley National Laboratory to develop resources to link the technical and human considerations that influence window and façade design, selection and use. Today, the EWC has built and grown the website that includes the residential Window Selection Tool, the Façade Design Tool for commercial buildings at, and related online educational information that receives more than 20,000 unique visitors each month. Under the banner of NFRC, these online resources will be enhanced to expand the benefits for the public and the overall fenestration industry.

“With the additional resources provided by NFRC, together the Efficient Windows Collaborate will now have the opportunity to reach a larger audience and continue to promote sustainable and energy-efficient windows as part of the larger green building movement,” said Kerry Harp, former Executive Director of the EWC.

From its start, the EWC’s mission has been to expand the market for high-efficiency fenestration products and to make ENERGY STAR and NFRC labeling a universal practice in the U.S. This acquisition gives NFRC the opportunity to extend its reach with new audiences and with organizations contributing to national energy-efficiency goals.