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Should you be using an internal or external solar control window film?

If you are reading this blog post at all, it is likely that you already understand some of the broad benefits window film can have for solar heat and glare control. Whether it is installed at a residential or commercial premises, the right window film can make a significant difference to the comfort of such buildings' occupants, while reducing pressure on air conditioning systems.

At this time of year, as temperatures gradually rise, many specifiers and end users alike feel an increasing urgency to purchase window films that will repel heat and lessen glare.

But it's not just a given window film's appearance or even performance statistics that should inform whether you select it for your own intended setting. That's because the question of whether a particular window film is meant to be internally or externally applied will also be a significant one.

These types of window film aren't directly interchangeable

The first reason to care about these two types of window film for solar heat and glare control, is that it makes a real difference to the performance and value for money you get out of your chosen film.

In a nutshell, a window film that is described as 'internal' is designed to be applied to the interior surface of a window. These internal films are processed in such a way that it is not recommended to apply them to the exterior surface of glass; they are simply not designed to withstand external conditions, including the varying weather and ultraviolet (UV) rays.

External films, meanwhile, are – as their name suggests – meant to be installed on the exterior surface of a window. They sport the tough, exterior-grade construction that internal window films lack, which means they won't prematurely degrade in harsh weather conditions. They also use a strong waterproof adhesive.

Different circumstances will dictate the window film you select

Ultimately, there are various factors that will determine whether you go for an interior or exterior window film. Cost can be one such factor, of course. But there might also be practical difficulties associated with attempting to install window film on a particular side of the glass, thereby forcing you to have the film applied to the other side instead.

Other customers of ours here at Stockfilms may choose an external window film because the type of glass involved - such as laminated, Georgian-wired or heavy-tinted glass, or even some double or triple glazing - doesn't lend itself well to an internal film.

Bear in mind, in particular, that an interior film would leave the glazing unit exposed to the sun from the outside, thereby increasing the thermal stress on the window.

Would you like to have a more in-depth discussion with our team with regard to the solar heat and glare control solution for your site that would enable you to rest easiest? If so, we are available to take your call, on 020 8441 0449; alternatively, simply fill in and submit our short online contact form.