I just received an exhaust hose insulation "blanket" off Amazon to fit onto my ancient portable a/c and it sure made a difference in how well it cools the room. I've always known about this inherent problem with these things but never bothered because it doesn't get used all that often. However the past few days have been miserable and it just wasn't cutting it in getting the room down past about 80 degs. A pretty cheap fix for around $20-$30 . I imagine just wrapping the hose with something else may works just as well if you're handy but right now I'm not handy LOL.