400CM (157") Universal Window Seal for Portable Air Conditioner and Tumble Dryer – Works with Mobile Air-Conditioning, Easy to Install - Air Exchange Guards with Zip and Adhesive Fastener

I buy a new one of these each year, as they can get kind of gross after being exposed to outside for many months. The one I previously ordered changed their design to have a “universal” hose attachment, which of course did not fit the hose of my AC unit. I came back to Amazon to find one that has the zipper style opening and found this product. I don’t ever use the Velcro tape that comes with these, because I find the adhesive usually doesn’t hold up and seems to dissolve from heat-I buy the strong outdoors Velcro tape and it works perfectly with this! Setting it up was a pretty straightforward and easy process, and now that it’s been up a couple of months, I can rest assured that it is doing its job. It has been holding up wonderfully so far-the zipper stays taught around the hose exiting to the outside, and it is doing great at keeping the hot air outside instead of inside. I highly recommend measuring to ensure you get the right size, I measured and the fit was perfect. For these weird French windows, I absolutely recommend this product to set up your portable AC! They’re also quite easy to take down when summer is over, thought with the Velcro I have been using, I definitely have a lot of adhesive left behind that I will eventually need to address, but it’s totally worth it to be able to keep my apartment cool during the summer!

I've been trying to install my portable AC into a casement window for a week now. I have an outward-opening casement which opens vertically from the bottom.Before this, I tried a bunch of stuff to seal the window kit provided with my AC. Even after getting a sheet of plexiglass cut for the window, my AC still was leaking too much heat back into the room, and the plastic from the window installation kit even warped itself. This was my last hope... and luckily it worked like a charm! I'm pretty sure I even accidentally ordered one slightly too large for my window, but it still fits and works fine after rolling up some excess material.Installation was super easy albeit a little tedious -- the instructions were kind of bad and the video instructions online were very poorly shot (there's an animated video and a real-life demo, both of which not super helpful), but it was pretty much just a matter of cutting two sets of 4 velcro strips - one set for the casement, and one set for the window frame.Then you velcro the "seal", but annoyingly you have to pick a specific side to velcro to the casement vs the window frame, and the only way to tell which side is to follow the edge all the way until it tapers off at the end. It would be really nice if they would color the velcro on one side in order to tell that it's the "wide" side vs the narrow side.I mentioned that I got one which is slightly too big for my window - I rolled up the extra material in the area where I wasn't able to finish getting a velcro seal, and taped it up with some painter's tape. They say to use elastic for this purpose, but didn't provide any. It's not perfectly sealed in that area, and I expect I might need to do a better job of rolling it up if there's another big heat wave in the area.Installing with two hoses is just as easy as installing with one -- it's just an extra zipper in the seal. I pointed them both downwards.After turning on the AC, there is very little heat being leaked back into the room, which is perfect! Like I mentioned, this is so far the only solution that has worked for my casement window. The material is high enough quality that I don't expect it to degrade significantly in the near future, the zippers move pretty easily around the seal, and overall I'm pretty happy with it.

Easy to install. Been using it for 3 weeks and the seal is nice and tight. Really made using our portable AC easy with casement windows

I can’t believe how well this works! I’ve had a nice portable AC unit in an upstairs room that has limped along for years. The plastic piece never fit the window, then it cracked and we just duct taped it, it was a mess. I kept the unit on 62 and it worked constantly and the room was still uncomfortable and too warm. When I saw this, i couldn’t figure out how it could possibly work, but I didn’t want to buy another kit just like the one I’d had. For the price I was willing to give it a try. I did the job myself! It took longer to clean the window frames and windows than it did to install it! When I put the hose in and zipped it up, I thought “there’s no way hot air won’t leak around that zipper, just no way.” I turned it on, the hot air went through the hose and out the window, the plastic filled out like a sail and formed a vacumn around the collar of the hose and it was like magic! The AC unit actually works the way it’s intended now. It’s get to temperature then backs off and kind of Idles, then blows cold air again, etc. It used to just work full out all the time and never could keep up. I’m actually having to turn up the temperature some days because it’s too cold! Unbelievable. For the price point, it’s incredible. It’s only been a week since I installed it, but it’s holding up fine and I’m so happy with it so far. My windows are the kind that slide up and down, not open to the side as shown in the advertisement. They’re large. I bought the 500 cm kit.