Before you decide that low-e window film is the right solution for your commercial building, make sure you’re not experiencing one of these issues:

• Moisture/condensation/mold. Window film can keep solar heat gain and glare out of your building, but it won’t keep moisture out when window seals or frames are damaged, ineffective, or failing due to age or poor window design.
• Air leakage. Drafts due to high winds, pressurization problems, or poor seals or gaskets often result in reduced comfort levels for tenants and occupants. While low-e window film may improve interior comfort levels as they relate to solar heat gain and hot/cold spots, it wasn’t designed to reduce or eliminate drafts or pressurization issues.
• Cracked or failed glass. Security window film is designed to hold glass in place upon impact, preventing or slowing glass breakage when a window is shattered (whether accidentally or on purpose). However, if existing window glass already has cracks, applying window film over the cracks won’t solve the problem – the window glass still needs to be replaced.
• Structural inadequacy. If the existing window system (including connections) isn’t structurally adequate, is deteriorating, or doesn’t effectively accommodate building movement and structural loadings, this can affect window performance (and safety). Window film does improve window performance as it relates to insulating power; however, window film can’t improve or repair the window’s overall structure. If your windows are structurally inadequate, you’ll need to look at solutions beyond window film to solve this problem.

– See more at: http://blog.vista-films.com/2014/08/what-window-film-can%e2%80%99t-do/#more-1158