Fitting window film to retain heat can lead to costly damage if the wrong type is selected, according to a window film expert.
Tomass Kundzins, window film expert at Glacier Tinting, said some films absorb more solar energy than others, which can change how the glass heats up when sunlight hits it. If the film isn't suitable for that particular window, it can increase the risk of the glass cracking.
Thermal stress risk
Thermal stress happens when different sections of a glass pane heat up or cool down at varying rates. Where solar controlled film is installed on your windows, it enhances heat absorption. Should the temperature variation become sufficiently high, it can lead to cracking.
Kundzins explained that two windows can look almost identical, but that doesn't mean they have the same glass specification. One might have a coating or be made from a different type of glass, and that can affect which films are suitable.
Check before you buy
The initial step is to establish whether your windows are single, double or triple glazed, and determine if there are any existing coatings present. Ensure you carefully read the manufacturer's compatibility guidance on any window film you purchase, as certain products are only appropriate for specific glazing types.
Kundzins advised being wary of buying film purely because it's cheap or has good reviews, as a film might work perfectly well on one person's windows and be completely unsuitable for somebody else's. He also recommended checking whether applying the film could affect any existing glazing warranty, particularly if your windows are relatively new.
