RESFEN is a PC program for calculating the heating and cooling impacts of windows in residential buildings for climates throughout the US.

With LBNL support, the National Fenestration Rating Council (NFRC) is developing an Annual Energy Rating for residential windows.

Using the MoWiTT field test facility, LBNL researchers have validated the performance claims of new window products used in the residential sector over the past decade, including first generation low-e windows, spectrally selective or low-solar gain low-e, and superwindows.

With results from the Infrared Thermography Laboratory, researchers have developed more accurate models of window heat transfer.  This increases the accuracy of the National Fenestration Rating Council's window ratings.  From related experiments, guidance on how to minimize condensation on the interior surfaces of windows has also been developed for the Efficient Windows Collaborative.

Efficient windows can greatly improve the thermal comfort of residential buildings during both heating and cooling seasons.  Research in conjunction with UC Berkeley's Center for Environmental Design Research is aimed an better defining Window Performance for Human Thermal Comfort.  Guidelines on how to best maximize thermal comfort have been developed for the Efficient Windows Collaborative.