Installing window film on certain Low-E or dual-pane (IGU) glass units can cause thermal stress or seal failure. It is critical to verify the glass type before installation.
A Low-E coating meter detects the presence and location (surface 1, 2, 3, or 4) of low-emissivity coatings on single or double-pane windows. Place the meter flat against the glass surface and press the test button. If a coating is detected on the interior surface (Surface 2 or 3 of an IGU), high-absorption solar control films should generally be avoided to prevent excessive heat buildup.
Always consult the manufacturer's film-to-glass chart before applying tinted or reflective films to dual-pane windows.