Quick Answer
Upgrading existing windows for better gain is possible, but it depends on the type of window and the extent of the upgrade. Replacing old, single-pane windows with low-E, double-pane units can significantly improve energy efficiency and solar gain. This upgrade can be done in various ways, including inserting storm windows, applying window film, or replacing just the glass panes.
Types of Upgrades
To upgrade existing windows for better gain, consider replacing old, single-pane windows with low-E, double-pane units. These upgrades can be done with various types of glass, including low-E coated glass, which reflects radiant heat back into the building. For example, replacing a single-pane window with a low-E double-pane unit can reduce heat loss by 50-70% and increase solar gain by 20-30%.
Techniques for Existing Windows
If replacing windows is not feasible, consider techniques like inserting storm windows or applying window film. Storm windows can be installed on the outside of existing windows to increase insulation and reduce heat loss. Window film, on the other hand, can be applied to existing windows to reduce heat transfer and increase solar gain. Some window films can reduce heat transfer by 30-50%, while also reducing UV radiation by 99%.
Measuring Performance
To measure the performance of upgraded windows, use metrics like the R-value (thermal resistance) and the solar heat gain coefficient (SHGC). The R-value measures the window’s ability to resist heat transfer, while the SHGC measures the window’s ability to transmit solar radiation. For example, a low-E double-pane window with an R-value of 2.0 and an SHGC of 0.40 can provide improved energy efficiency and solar gain. Consider consulting with a professional to determine the best upgrade options for your specific windows and climate.
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