(0.9 CEU; 55 minutes) Storm windows are an underrated energy-conservation retrofit, especially since energy specialists have been installing low-e glass in storm windows. Although there may be some low-e acrylic glazing, glass is really the only low-e glazing currently used for storm windows. Acrylic glazing allows more infrared radiation out through interior storms during the heating season compared to glass. However, acrylic is a good choice for low-cost interior storm windows that customers make and install themselves. Interior glass storm windows serve as a second window that roughly doubles the R-value of existing single pane windows. Glass interior storms increase the R-value of existing double-panes by 30 to 50% and come in frames that allow a permanent installation instead of requiring seasonal installation and removal.