Jeld-Wen.
The company, a 2010 Energy Star Partner of the Year, offers an energy resource section on its Web site with information on the energy tax credits, a tutorial on glass performance, guidelines on Energy Star zone requirements, and a list of qualified models. The site also lists thermal performance ratings for all of its window products. Pictured: Custom wood window with metal cladding. 800.535.3936. www.jeld-wen.com.