Efficient Windows Collaborative
This site provides information on the benefits of energy-efficient windows, descriptions of how they work, and recommendations for their selection and use. A fact sheet on "Selecting Energy Efficient Windows in Wisconsin" can be downloaded from their website.
National Fenestration Rating Council
The NFRC provides consistent ratings on window, door, and skylight products. Their website describes the rating system and provides consumer information on different types of windows and skylights.
