Low-E Storm Windows

Cutaway of a low-E storm window with two orange-yellow arrows hitting the window and reflecting back inside.

Low-E coating on the glass reflect heat back into the room during the winter months.

Storm windows can reduce heat loss through the windows by 25% to 50%, and low-E storm windows save even more energy. They not only have the benefits of regular storm windows, providing an additional insulating barrier and reducing infiltration, but the low-E coatings (microscopically thin coatings applied to the window glass) help keep heat inside during the winter and outside during the summer.

Chicago low-E Storm Window Study

HUD's PATH program, along with the DOE and industry partners, sponsored a field evaluation to investigate the performance of low-E storm windows. The local weatherization agency in Chicago identified 6 older homes with single pane windows to use in the study.

Energy usage measured in the winter of 2005-2006.
Monitoring began with single pane windows in late October 2005
Low-E storm windows were added in January 2006
Monitoring continued through March 2006

Conclusions from Chicago Study

Clear glass storm windows reduced the whole house heating load by 13% with a 10 year simple payback.
Low-E storm windows reduced heating load by 20% with less than a 5 year simple payback.
Reduction in summertime cooling requirements may also provide additional energy savings.

Image of graph showing the effects of adding low-E storm windows to existing windows.