What kind of window film to cool down room? DIY option?

[lifejoy]

My daughter’s room is south-facing and too hot at night! Anyone have any pro tips for applying UV/IR reflective window film to keep the heat out?

[Sibley]

Have lots of space, patience, and plenty of time. It's not technically difficult, but it's a PITA.

[gooki]

Have you tried bubble wrap?

[Michael in ABQ]

Our first rental house years ago had a large open room with high ceilings. There were a few windows set high up and in the afternoon the sun would come in those and the evaporative cooler (like A/C but not as good) could not keep up. I went to Lowe's and bought a roll of window film for reducing heat. Worked great. It was noticeably cooler after just placing it on those three high windows - which of course didn't have blinds. There were a few larger windows facing the same direction but they had blinds which blocked a lot of the heat. It was a bit of a hassle to apply but because the windows were high up any minor bubbles or imperfections in the application weren't noticeable. Even if they were, it was totally worth the hour of labor and $20-30 for the increased comfort (and reduced electrical bill).

[Shinplaster]

We used this on our south and west facing windows.    https://www.homedepot.ca/product/gila-light-heat-control-window-film-3-feet-x-15-feet/1000686185      This one is almost invisible when installed, and has stood up well for over 10 years now.   We're moving in a couple of weeks, and I intend to reorder and use it at the new house too.  (older windows without the anti-glare, etc. gas between the double panes).

There are thicker ones, and we did try the titanium one on the patio door.  Did not like that one!  Harder to install, and darker tint means you don't see through it as well when you're inside.

There are two layers of film in the roll - one is the mylar backing, and one the actual film. (for the reviews that said it fell off the window, um yes, they didn't take the backing off!).     Make sure which is which, and be very careful to not get dust, hair, etc. on the back of the actual film when you separate the layers.  Do all the cutting/fitting with the backing attached, and put it up much like mac tac or vinyl peel and stick shelf liner.  Spray the window (be generous with the water), peel back a small area at the top, get that set, and then work your way down the window.  Keep the area to be done well wetted.

Do not follow their instructions though re: solution, etc.!   You don't need anything but a spray bottle with just water in it - no detergent, etc.   And don't use the squeegee provided.   A plastic credit card works much better, (work at about a 45 degree angle to the film) and allows you to work smaller areas to get the air bubbles out.   There will be a few stubborn small air/water bubbles the first day, but as the film dries most will disappear.  If not, pierce with a small pin and rub with a towel or microfiber cloth.   It will make a mess on the floor - put down towels to catch the water you squeegee out.    If you ever want to remove it, just peel it off.  Leaves no marks, etc.

[HPstache]

We also used Gila window film on our west facing windows.  So far we are really happy with it!  In the summer we wish we would have gone darker, but in the winter we like that you can still see out.  Ours are shiny facing outward,  so its difficult to see in, but we like that for privacy.  It's on our sliding patio door.

[Dicey]

I have no experience in this area. Just responding because it's always nice to see you here. Hmmm, anything new going on in your life these days @lifejoy?

[Fishindude]

Good heavy blinds or curtains will do about as much as anything.

[TrMama]

We used this on our south and west facing windows.    https://www.homedepot.ca/product/gila-light-heat-control-window-film-3-feet-x-15-feet/1000686185      This one is almost invisible when installed, and has stood up well for over 10 years now.   We're moving in a couple of weeks, and I intend to reorder and use it at the new house too.  (older windows without the anti-glare, etc. gas between the double panes).

I used the same film on our south facing windows several years ago. I didn't find it made any difference at all. This spring it started flaking badly so I removed it. Again, I haven't noticed any difference in how hot those rooms get. At least it was pretty easy to remove. Thought I'd be scraping at it forever, but it came off neatly in one piece using some water sprayed between the film and the glass.

Those windows now all have blackout curtains, which seem to work better.

[Shinplaster]

We used this on our south and west facing windows.    https://www.homedepot.ca/product/gila-light-heat-control-window-film-3-feet-x-15-feet/1000686185      This one is almost invisible when installed, and has stood up well for over 10 years now.   We're moving in a couple of weeks, and I intend to reorder and use it at the new house too.  (older windows without the anti-glare, etc. gas between the double panes).

I used the same film on our south facing windows several years ago. I didn't find it made any difference at all. This spring it started flaking badly so I removed it. Again, I haven't noticed any difference in how hot those rooms get. At least it was pretty easy to remove. Thought I'd be scraping at it forever, but it came off neatly in one piece using some water sprayed between the film and the glass.

Those windows now all have blackout curtains, which seem to work better.

Well that's strange.   Our film has never flaked, and it's been years.  I didn't need to spray water to remove one small section last year either - it just peeled right off.  The film was still as soft and pliable as it was the during installation.    They do make several different varieties - I wonder if ours was different than yours?  Or have they changed the product?  We did notice a big reduction in heat - Mr. SP's favourite chair is right by 4 of these windows, and he said it was instantly more comfortable on hot sunny days. 

I tried their 'titanium' (or some such nonsense name) on the patio door, and that was a whole other unpleasant experience.  It had some sort of glue/sticky stuff on the back, and was much harder to work with!   I expect that one will also be a pain to remove, but thankfully we won't be here for that.  (moving in 2 weeks!).

[phildonnia]

We used this on our south and west facing windows.    https://www.homedepot.ca/product/gila-light-heat-control-window-film-3-feet-x-15-feet/1000686185      This one is almost invisible when installed, and has stood up well for over 10 years now.   We're moving in a couple of weeks, and I intend to reorder and use it at the new house too.  (older windows without the anti-glare, etc. gas between the double panes).

[...]

Do not follow their instructions though re: solution, etc.!   You don't need anything but a spray bottle with just water in it - no detergent, etc.   And don't use the squeegee provided.   A plastic credit card works much better, (work at about a 45 degree angle to the film) and allows you to work smaller areas to get the air bubbles out.   There will be a few stubborn small air/water bubbles the first day, but as the film dries most will disappear.  If not, pierce with a small pin and rub with a towel or microfiber cloth.   It will make a mess on the floor - put down towels to catch the water you squeegee out.    If you ever want to remove it, just peel it off.  Leaves no marks, etc.

I've used the same product with great success, and it's still looking fine after ten years.  One thing I learned the hard way: make sure you use a very sharp knife to trim the film to the window.  Like a brand-new box-cutter; not some old rusty X-Acto you found in a tool box.  If it snags while cutting, the film tears apart very easily. 

[HPstache]

We used this on our south and west facing windows.    https://www.homedepot.ca/product/gila-light-heat-control-window-film-3-feet-x-15-feet/1000686185      This one is almost invisible when installed, and has stood up well for over 10 years now.   We're moving in a couple of weeks, and I intend to reorder and use it at the new house too.  (older windows without the anti-glare, etc. gas between the double panes).

[...]

Do not follow their instructions though re: solution, etc.!   You don't need anything but a spray bottle with just water in it - no detergent, etc.   And don't use the squeegee provided.   A plastic credit card works much better, (work at about a 45 degree angle to the film) and allows you to work smaller areas to get the air bubbles out.   There will be a few stubborn small air/water bubbles the first day, but as the film dries most will disappear.  If not, pierce with a small pin and rub with a towel or microfiber cloth.   It will make a mess on the floor - put down towels to catch the water you squeegee out.    If you ever want to remove it, just peel it off.  Leaves no marks, etc.

I've used the same product with great success, and it's still looking fine after ten years.  One thing I learned the hard way: make sure you use a very sharp knife to trim the film to the window.  Like a brand-new box-cutter; not some old rusty X-Acto you found in a tool box.  If it snags while cutting, the film tears apart very easily.

Agreed.  You can buy the install kit for it that includes the spray material, a squeegee and a special knife for the job.

[Villanelle]

We recently did this.  Probably the biggest thing we learned was that there was no such thing as too wet.  You can use either windex or water with a bit of dish soap (we used mostly the latter).  Have it in a spray bottle.  We sprayed as we removed the backing (so that no static charge would draw lint or hair onto the film.  Then we applied it to the window--lots, until it was dripping.  Then we put the wet film on the wet window. 

We also tried two different methods--one with pulling back the backing a few inches, then applying the film to the window, then removing the backing as we moved down the window.  The other was just removing the entire backing and then placing it on the window.  The latter was  far, far superior.  Much easier. 

If you don't need or want the light, they also make black out film.  It's thicker than the tint (and therefore even easier to apply).   And because it is opaque, you don't have to worry about tiny bubbles or lint.   This is the one we used.  https://www.amazon.com/gp/product/B07F2ZH2GT/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1