Cold Climate Window Insulation Evaluation
Windows are a major source of heat loss in a building envelope and a potential source for mold and rot if unmitigated condensation occurs. Because upgrading to high-performance triple-pane windows is expensive, homeowners have found other methods to reduce heat loss through their windows. Some of these techniques, however, can excerbate condensation issues.
This study builds upon CCHRC's existing research on moveable window insulation. In 2011, we compared nine different window treatments in terms of thermal effectiveness, affordability, ease of installation, durability, functionality, and condensation resistance (found here). This new window treatment consists of adding a 4” tall layer of Expanded Polystyrene (EPS) foam board pressure fit into the exterior frame of the window against the outside of the glass. This 4” EPS covers the bottom portion of the window, where most condensation occurs while leaving the majority of the window with a clear view of outside.
Our primary question is: Is placing foam board on the exterior of the window frame an effective solution for increasing a window’s condensation performance?