brand new windows already cracking - anyone else had this happen?

Yeah, that does sound a bit off to me too. I've had new windows installed twice now (different houses), and honestly, never saw cracks popping up like that. Stress cracks can happen, sure, but usually they're pretty rare and more common with older windows or extreme temperature swings. Two months in seems way too soon for that kind of issue.

One thing I'd check is whether the installer used shims properly or if the frames were forced into place. If the window frames are under tension because of improper installation, that could definitely cause stress cracks. Also, double-check your warranty paperwork - most reputable window companies cover stress cracks within the first year or so.

I'd probably push back a bit on the installer and ask them to come out and inspect again. Maybe even get a second opinion from another contractor if you can swing it. Better safe than sorry, especially since windows aren't exactly cheap...

I've seen this happen a couple times, and honestly, it's usually down to installation issues rather than the windows themselves. Even high-quality windows can crack if the frames aren't squared up properly or if they're jammed into openings that aren't quite right.

If you're comfortable doing a quick check yourself, grab a level and see if the frames are sitting straight and true. Look closely around the edges - if you notice uneven gaps or spots where the caulking looks stretched or compressed, that's a sign something's off. Also, gently press around the frame edges; if there's noticeable flex or movement, that's another red flag.

Definitely worth getting the installer back out to take a look, but I'd also snap some clear photos of the cracks and framing issues first. Having visual proof can help if things get tricky with warranty claims or disputes. And yeah, a second opinion never hurts - especially if the original installer seems hesitant or dismissive.

Since these appeared only two months after installation, document the crack pattern before anyone replaces the glass:

- Check whether each crack begins at the edge of the pane and travels toward a corner. That pattern can be consistent with thermal or frame stress, although it isn’t proof by itself.
- Impact damage more often has a visible point of impact, sometimes with a small bullseye or radiating lines. Don’t press on the glass while checking.
- Photograph each crack with a ruler for scale, plus wider shots showing the sash and frame. Note the room, pane, date, and whether the crack changes with temperature.
- Ask the installer to have the glass supplier or a qualified glazier identify the failure mode in writing. The edge-to-corner pattern may help distinguish installation stress from accidental damage for warranty purposes.

A level check can be useful, but it won’t diagnose glass failure on its own.