Interesting point about the energy savings. I've been wrestling with city noise myself for years, and honestly, I hadn't really thought about the heat...

Sounds like a solid DIY solution, but I'm curious—did you notice any condensation buildup between the insert and original frame? I've heard mixed thin...

Haha, been there myself—caulking is deceptively tricky, isn't it? Curious though, did you notice a big difference right away, or did it take a while t...