The amount of money saved depends on the type of film chosen and certain property-specific variables (building use, location, climate, existing energy costs, HVAC system, glass-to-wall ratio, etc).
Sun Control Window Films are designed to reduce an existing window’s Solar Heat Gain Coefficient (SHGC) while Insulating Window Films are designed to reduce a window’s SHGC and U-Value. Reducing a window’s SHGC helps to reduce solar heat gain in the summer. Reducing a window’s U-Value helps to reduce heat loss in the winter.
A sun control window film will reduce solar heat gain in the summer as well as the winter months, which means that heating consumption may increase while overall annual consumption decreases. An insulating window film will reduce solar heat gain in the winter (and summer) but also helps retain man-made heat created from the heating system. That translates into using less energy 12 months out of the year.
Keep in mind that window film only impacts the performance of a building’s windows. If the ratio of window area to wall area is low, then window film will have minimal impact on cooling and heating costs. The higher the ratio, the more of an impact window film will have.
Ultimately the savings come from using the HVAC system less. If a building does not have existing air conditioning, adding window film will not reduce cooling bills because there is no cooling to begin with.
For a large building, window film usually pays for itself within 5-7 years, and that does not take into consideration utility rebates, government grants, carbon footprint reduction mandate penalty avoidance, rising energy costs, and general inflation. After obtaining some basic information, including energy consumption and spend for a given building, we can conduct an energy audit to estimate the annual dollars saved by various window films.