National Fenestration Rating Council Fact Sheet on Windows

National Fenestration Rating Council Fact Sheet on Doors

The National Fenestration Rating Council maintains a database of rated windows, skylight and door manufacturers.

Department of Energy Consumers Guide to Windows, Doors and Skylights

Department of Energy Energy Efficiency and Renewable Energy Consumer’s Guide Improving the Energy Efficiency of Existing Windows

Energy Star Consumer Information Residential Windows, Doors, and Skylights

Energy Star 2007 Partner Resource Guide Windows, Doors and Skylights 

Efficient Window Collaborative

Efficient Windows collaborative Fact Sheet for choosing windows in New York including NYC