Good call on the thermostatic valve. Had a similar issue at our old house—every time someone flushed, you'd brace yourself for the ice age in the shower. Thought about doing the valve too, but decided to check the pressure balance first. Turned out our main pressure regulator was shot, causing big fluctuations. Replaced that and added a pressure-balancing shower valve as extra insurance...haven't had a cold shock since. Guess it depends on your specific plumbing setup, but definitely worth looking into both approaches before tearing into walls or pipes.
Had something similar happen here, and before diving into valves or regulators, I checked the simple stuff first. Turns out our toilet fill valve was old and hogging water pressure. Swapped it for a newer, low-flow model...problem solved without opening walls. Worth a quick check maybe?
"Turns out our toilet fill valve was old and hogging water pressure."
Interesting point, though from my experience, even a newer fill valve might not fully solve it. Older plumbing setups often have undersized or corroded pipes, so sometimes upgrading to a pressure-balanced shower valve is unavoidable...especially in older homes.
Good catch on the fill valve—I had a similar issue in one of my older rentals. Replacing it helped a bit, but honestly, the real fix was upgrading to a pressure-balanced valve in the shower. Older plumbing can be tricky...pipes narrow over time with corrosion and buildup, so even new fixtures can't always compensate fully. Still, swapping out that fill valve is a solid first step and might buy you some time before tackling bigger plumbing upgrades. Plumbing issues in older homes are always an adventure, aren't they? Hang in there, sounds like you're on the right track.
"Older plumbing can be tricky...pipes narrow over time with corrosion and buildup, so even new fixtures can't always compensate fully."
Yeah, learned this the hard way myself. Replaced the fill valve thinking it'd solve everything—nope. Still get that icy blast occasionally. Guess a pressure-balanced valve is next on my list...homeownership joys, right?
