This $5 Film Stops 80% of Heat Coming Through Your Windows. Why Do They Sell You New Glass Instead?

Your windows let in way more heat than you think. The Department of Energy says they're responsible for 25–30% of your home's heating and cooling energy use. That's 15% of your wall space doing a third of the damage. And the fix most people get sold? Ripping the whole thing out and starting over for $700–$1,000 per window. There's a faster answer that's been sitting in the wrong aisle of your hardware store for decades. It installs in 20 minutes with soapy water and a squeegee. It lasts 15–20 years. And it delivers 70% of the performance of a full window replacement at a fraction of the cost. In this video I break down the science behind how it works, what it does to your energy bill, why the window industry will never mention it, and the one situation where it's not the right move. If you've installed window film and measured a difference, drop your results in the comments, it helps me figure out what to cover next.