Had vinyl in my last place—looked fine for the first few years, then one summer the west-facing windows started sticking. By year six, frames were so warped I had to wedge them shut with a paint stick. Switched to aluminum with thermal breaks in this house. Spent more upfront, but I’d rather pay once than fight my windows every July. Finding someone who actually knew what a thermal break was took three phone calls and a lot of “uh, let me check with my boss.” Worth it, though.
That’s interesting about the vinyl warping—had a similar thing happen here, but it took a bit longer to show up. My house faces south and gets hammered by sun all summer. The vinyl frames looked brand new for maybe eight years, then started bowing just enough that you could feel the air leaks around the sashes. I never had them stick, but they definitely lost their snug fit.
I’ve looked into aluminum with thermal breaks, but honestly, I was skeptical about how much difference that “break” really makes for insulation. After seeing a neighbor’s install, though, I’m starting to come around—his frames actually stay cool to the touch in August, which surprised me. Upfront cost is tough to swallow, but the idea of not having to constantly caulk or fight sticky windows is appealing.
Funny you mention the contractor confusion—when I called around, half the folks didn’t seem to know what low-e glass was either. Makes you wonder how many people just get whatever’s in stock...
Had the same issue with vinyl—mine started warping after about ten years, mostly on the south side where the sun just bakes everything. Here’s what I did: First, checked for drafts and tried caulking, but it was a losing battle. Switched to aluminum with thermal breaks last year. Honestly, the frames don’t get nearly as hot as I expected, and no more fighting with sticky sashes. Price wasn’t fun, but I figure less hassle down the road is worth it. Contractors definitely seemed hit or miss on the details... had to double-check everything myself.