While low-emissivity glass – or low-E glass as it is commonly described – can be a highly invaluable form of glass for preventing heat from escaping through a building’s windows, you may understandably have other needs that could be served by an appropriate window film.
A low-E coating on glass, after all, may be excellent for boosting a household or business’s energy efficiency while reducing monthly bills and minimising the building’s carbon footprint, but it doesn’t address other needs that occupants may have – for example, to reduce glare or enhance the safety of the windows.
This is where the right window film can come in, which may lead you to ask the question: “can window film be used on low-E windows?”
The short answer is yes, it can be... but there are also some other factors to bear in mind.
The type of low-E coating makes a big difference
The biggest question is not so much whether window film can be used on low-E windows, but instead whether it should be.
How you answer this question for your own building will depend on such factors as the type of low-E surface used on your glass, as well as where the low-E surface is located in the window system, and what effects you desire from your window film in terms of minimising heat gain, reducing heat loss or other potential benefits.
Two basic types of low-E window surfacing exist. One of these is a conductive coating that is applied to glass during its manufacture, while the other is a more complex arrangement of multiple layers of metals and conductive coatings. This latter type is only deposited on the glass once it has been made.
The first type of low-E glass can help slightly in reducing the amount of heat that escapes from a building, but isn’t very effective at keeping heat levels low in a building in hotter conditions. The second type, though, is renowned at reducing heat within a building in this way, while also minimising how much heat is lost from a building through its windows.
If, then, you are buying window film with the specific intention of reducing heat gain within a building, it could work very well on low-E glass of the first, less effective type.
But location is a major factor, too
However, the wisdom of using window film on low-E glass will also be largely determined by the exact location of the low-E surface in the window system.
For example, if the low-E coating is on the room-side surface of the innermost pane of glass, using window film may make the low-E glass less effective at reducing the amount of heat lost from the building, or eliminate this benefit altogether. This might not be such a great concern, however, if your chosen window film also offers strong heat loss reduction.
It is much more common, though, for low-E window systems to consist of double pane windows in which the low-E surface faces the air space between the panes. If this is the case for your own low-E windows, you will be able to install window film without the glass’s existing heat loss reduction benefit being eliminated.
The specific form of window film that you should select for your building will hinge on factors like the above and the other purposes that you intend the window film to serve – for instance, to reduce glare or limit heat gain in the building.
If you are yet to have low-E windows installed in the given building, however, or if you desire a low-E effect for existing windows, we are pleased to be able to offer dedicated low-E window film that offers a host of other benefits alongside the traditional greater retention of heat within a room.
So, can window film be used on low-E windows? Yes it can be, but you will need to take into account all manner of practical factors and the intended benefits when you are looking to select a window film that can be depended on to deliver worthwhile results.