Not the commenter above but can answer this. Film is nearly always applied to the inside of the glass. Most film types, if placed outside, are quickly destroyed by the sun and elements; i.e., will eventually peel or flake up and fall off. Exterior films are a specialized and generally more expensive product, and likely not necessary for the application described here.
Redditmodstouchgrass@lemmy.zip 22 hours ago
I figured, but when i looked it up a couple people were saying to put it outside, but one of those said double paneled windows would crack if it got too hot, so it might just be those cases.
Septimaeus@infosec.pub 21 hours ago
There is a combination of full mirrored rejection film (often not allowed in urban apartments) + prolonged intense sun exposure + certain types of sealed double pane windows which can lead to overpressurization of the interior chamber by both doubling the intrapane greenhouse effect while thermally insulating one side with film. Though IIRC this usually results in the glass perimeter seals failing (like a “blowout” which defeats some of the thermal barrier function of the double pane glass) rather than glass cracking (usually associated more with rapid thermal changes, such as from certain styles of compact vertical ejection window ACs).
But the type of thermal rejection film described above is not so aggressive as that. If the window is double pane and has a lot of direct sun exposure, you could ask an installer or consult with a store that sells these window treatments in your area to get an idea of the risk given local climate and specifics of your window for peace of mind. They might be able to recommend some film specifications as well.
Redditmodstouchgrass@lemmy.zip 20 hours ago
So before I go to my smart-ass landlord about this, are these films easily removable if necessary?
NihilsineNefas@slrpnk.net 4 hours ago
The way the transparency thing works is similar to a two way mirror; they’ll always let light through, but at night the light from the outside isn’t bright enough to overpower the light from inside, which is what makes the outer layer a mirror
There are some which reflect about 95% of the light and practically 100% IR that are made of mylar foil like an emergency thermal blanket, think that’s what theyre talking about
Septimaeus@infosec.pub 20 hours ago
Yes, I’m not aware of any designed to be permanent, since most films eventually have to be replaced. The easiest to remove use static cling without adhesive. Those can just be ripped off in one piece, if you needed to demonstrate.