My mom lives out in the southern California desert and in this current heatwave it is typically 100 to 110 degrees outside. She has a 46" x 46" single pane glass window that is facing the sun a good portion of the day in the front of the house. Even though there is an awning outside the window, it still gets some direct sunlight and gets very hot. She had a thin piece of tinted film and some cardboard hanging in front of the window which probably helped a tiny bit but I heard about these types of reflective insulation and thought I would try some of this to put over the window to see if it worked any better.

She needs to be able to take it down, so I cut a piece and folded over the top and put several wide washers with a nut and bolt through the insulation so I could hang it right against the window with a spring loaded curtain rod. I felt how hot it was in front of the window with the thin film hanging and came back the next day after this new insulation was installed in front of the window and the difference was night and day. It is pretty thin at only three millimeters but it definitely cut down the heat level very noticeably.

It does come in a roll, so it took some rolling the foil the opposite way to get it to lay flat against the window without it curling. Hopefully over time, it will straighten out 100% from its own weight and from being warm. I did notice that the film does have a grid of the small holes in it that people have mentioned but in this roll they are very small and not noticeable unless you really look for them with direct sun behind the insulation. In the picture I attached you can not see them at all. This film is not what I could call inexpensive but I would definitely say it is a good purchase for the benefit received.

I have a campervan with a pot of windows. This is the perfect solution to cold nights. I cut squares with a knife and then put them into the windows and closed the windows so it's stuck in the window frame. It has kept the interior significantly warmer on cold (30 degree F) nights. I would suggest this product to anyone looking to use it for that purpose. I put my hand to it and feel no cold from the usually freezing window glass coming through. It also does not let much light through so it's good to have for my projector as it makes daytime use much more effective. Excellent product, highly recommend. Very easy to roll up when not in use to minimize used space.

I used this to insulate a small area of my basement for indoor seed starting. Previously that area was very cold, and had effectively no insulation between it and an outdoor crawl space (aside from a few semi-loose plywood boards), and the area was also on top of a big poured concrete pier/slab thing. So basically, the air was around 50 F in the winter and the surfaces were cold. Also, drafts (outside air) came in from the crawlspace through slits between boards. This is despite all the seed starting gear (lights, heating mats, etc.). In previous years I have even put a small space heater down there in an attempt to try to get the soil up to 60 F+, which is where I want it to start things like sunflowers.

So I bought a 50-foot roll of this stuff and cut three 14-foot strips of it. I tacked one long strip along the area that meets the crawlspace. (Used a staple gun"”not sure if that's the right choice, but it's what I had.) I also laid a long piece on the concrete surface (no attachment, just laid it down and put plant mats directly on top of it), then added a third piece that ran between that surface bit and up to the wall/crawlspace interface. I stapled the that third piece onto a wooden beam, and used packing tape to attach the lower pieces where drafts were trying to blow through. This allowed a mostly leak-free insulation shield about 6 feet "high" by around 14-ish feet wide. I put back the same temperature monitor that had read 50, and within a few minutes it was up to 55. Hmm. That's good.

After I reinstalled all the seed starting stuff (a few low-power heating mats, four low-power LED lights), the temperature went up to 65 degrees and stayed stable (!!). I have seen a few dips overnight down to 62, but in general this area that was consistently 50 degrees F (WITH lights and heating pads) is now mostly 65 and up (at one point it reached 70, which is actually pushing it as far as seed starting is concerned). The space heater is gone"”it would be way too hot at this point, and in fact I'm considering adding a fan or something, triggered in case the temp gets close to 70, just to circulate some of the heat away.

For the price, I'm extremely impressed. This stuff definitely created a thermal barrier between the super-cold cement block that the seedlings sat on"”that block is such a huge mass that there's no way a heating pad is going to ever warm it up (remember, we're in a basement and this is essentially a secondary foundation wall that just happens to be super wide). The insulation also created at least a basic vapor barrier on the interface w/crawlspace, blocking a lot of drafts and little gaps. The fact that it's so thin and easy to work meant I could also tack it up around edges and corners, which is where the drafts were the worst. I know this isn't really designed to be the only insulation in this use case (I might have been better off installing batts of fiberglass, and would certainly do so if I were trying to treat an entire basement), but it's cheaper, MUCH smaller, MUCH easier to work with, AND you can wipe it down (within reason"”it IS possible to rip the shiny surface). If you're looking for something very thin with a good radiant shielding effect, this is it.

The only downside I can think of is that the material is thin. While this is usually a positive, you do need to be careful with it, as it's possible to rip the foil layer and have it start peeling off. That's different from a lot of other kinds of insulation (fiberglass batts, foam board, spray...) where the material itself is real tough and workable. This is thin and precise"”install accordingly.

Used in rv. Was easy to cut and install in rv windows. Helps maintain temperature in rv. During the day in the summer our ac has a hard time keeping our rv cool. Noticed after installed in windows of rv, the rv was able to maintain temperature a lot easier. Great investment.

used it in summer for glaring sun on rv windows and will do a good job in winter to insulate the windows from the cold too