Ive used these in a northern freaking cold state & in a mid-range warmer state where we only get 1-3 months of true winter. They WORK! Saves me so much on my electrical bill, keeps my birds & spiders alive that are by the window. It is very easy to put on (helps if you have an extra set of hands). Its VERY easy to take off, & the tape generally comes off with it (unlike other brands I've tried). I have a very nice 2700 sq ft house. Electric isn't cheap here. Its propane heat & water heater. With this my bill has never been much over $300 during a brutal winter here with ice storms so bad we were basically snowed in for 2 weeks. (I live on a mountain). The amount this saves you will more than makeup for the cost of purchasing it. I must note... DONT forget to strech it with the hairdryer or it wont do much good.

Background:
 I have two patio doors—one in my bedroom and one in my front room—both leading to the balcony. They let out a ton of heat, making the apartment feel frigid even when the thermostat reads 70°F. Even a space heater couldn’t keep things warm for more than 15 minutes. Since my furnace runs on gas, this was getting expensive fast (my bill hit $267). That’s when I decided to try an insulation kit—and I’m glad I did.

Review:
 Installation was straightforward. The tape went on easily around the window frame, and cleaning the surface beforehand really helped it stick properly. After letting the tape set, I applied the plastic wrap. If you can, having a second person helps a lot—otherwise it can be tricky to keep the plastic from sticking too early or getting the tension just right. Still, I managed on my own.

Right after installing it, I noticed a huge difference. The cold air coming from the balcony doors disappeared, and the plastic formed a bubble-like insulating barrier. When I touched it, it felt slightly cool at first but quickly warmed up, likely from body heat—proof that it’s doing its job.

Afterward, I turned on the furnace and used a space heater briefly to bring the temperature up. Since then, I haven’t needed to run the furnace for hours. My apartment now maintains a steady 71–72°F, and I typically keep it at 70 during the day and 68 at night without issues.

Final Thoughts: 
I’m extremely satisfied with this product. It made a noticeable difference in comfort and energy usage, and I’ll definitely be buying it again next winter.

We bought a 1922 Craftsman home a couple of years ago and after the first winter replaced all of the old aluminum windows that a previous owner put in with vinyl, but during our second winter found that didn't help in the living area where there are 3 very large original picture windows (which we don't want to replace as they add to the charm and resale value of the home). So this winter I decided to insulate the interior of the picture windows with this film from Frost King. I bought the largest size possible and really struggled with the first window (took about 2 hours to fully install) but by the time I got to the third, I had it down and was able to complete it in about 30 minutes. Overall it's a good product, but I continually had problems with the adhesion tape -- it just doesn't stick well to the wooden frame particularly if you're using any sort of glossy paint. I had to reapply and/or reinforce in multiple areas. For this reason it gets 4 stars and not 5.

Some strategies I used for the larger windows that I learned:

1. Make sure the window frame that you're putting the tape on is clean and dry with no chemical or soap residue.

2. Put the strip at the top of the window on first and let it set for 10-15 minutes before peeling the backing off, this helps with adhesion to the frame.

3. Peel the backing off of the strip at the top of the window and place the film firmly and tautly there before peeling the backing off of the adhesion strips on the rest of the frame. This will help prevent the film from inadvertently sticking to the tape around the window causing you to have to pull it up and either ripping the film or removing the tape.

4. If you have a big picture window with divider lights (like I do) consider placing adhesion strips on the divider light frames as well, this will help get a tighter fit.

5. Once the top of the film is in place, peel the backing off the sides. I did a little bit on each side of the window and slowly went down each side pulling the film into place to ensure the tightest fit. The key is to make sure the film is as taut as possible before you apply the heat at the end.

6. Finish with the strip on the bottom - peel that backing off last and place the film onto the tape.

7. Apply heat starting at the top and working your way down then across. At least that worked best for me.

Note that in the past I've used similar products and had problems removing the tape from the window after the season is over, resulting in having to repaint the window frames. I will be updating this review at the end of the season to report on my experience with removing the product. Since the tape was so difficult to adhere to the windows to install, I am hopeful that it will be easy to remove.

This window shrink does what it is intended for. I should’ve thought a little more into my application before purchasing but that is on me.

Install was simple and overall it was very effective. My issue was actually my cats. Of course they saw this film in front of the windows and decided that they didn’t prefer it. One paw swipe and it was done.

Aside from that nuance that effected me, I think these are what you’re looking for if your looking to insulate some interior windows…. And you don’t have cats!

Sliding glass doors are so insulated...

We decided to keep it up year round and save on the A/C as well!

Worth every penny!!

What could be easy installation, can easily become a mess. The tape sticks as it should but also gets caught up on the plastic & causes fitting issues, as well as sticking in wrong places (it's of course double-sided invisible tape), the tape will still to a paint job depending on what type of paint is used, & when it peels off it can leave stripped paint spots showing. The plastic covering comes folded to fit smaller than size chosen so when its cut to fit window, open cut piece out (fan it out) so then you'll see it fits double window almost all the way. Don't rid yourself of any pieces until completely finished. I'm not sure if I'd recommend this product yet. The ease of use is menacing. I feel it has some insulating effect, I did not feel the air flow once I finally got it all on the window & sealed.

This works pretty well, easy to install. Does it take long?

This shrink window kit saved our heating bills during last winter. I can only imagine what my gas bill would’ve been without it.

I couldn't believe that it would work.

It actually does.

Finally warmer room.

I received an aged and beaten up box of this kit - picture attached.

This was proven with the double sided tape that would barely stick. Plus after the hair dryer was used to tighten the film, multiple parts of the tape would pull away from the frame, rendering the product useless.

Yes, instructions were followed and the I've used similar products before.

(In fact on the very same order, the Duck brand kit that was purchased at the same time, that box was fresh and the double sided tape had no such issues , and heat shrinking was easy & perfect ).

Amazon US should really be ashamed of themselves.

This product is good enough.

The size is perfect to enclose my small front porch where my dog likes to lie in the sun. It keeps the wind away so the house stays fairly warm and/or cool. Reasonably easy to install given the size of the area covered and the fact that it is shrinkable means that it is almost invisible.

Fue una salvación, mantiene la temperatura del cuarto en la madrugada ya no se filtra tanto el frío