Wondering if anyone has done this.
I have converted my showers to the external style of thermostatic shower valve. Made a huge upgrade to showering UX. Why not do the same for bathroom faucets?
It seems the same benefit could be had with the bathroom faucet, but no bathroom faucets in local shops have this capability (I didn’t check online nor would I shop online). So to wash my hands (or whatever), I start with full blast hot water to get the hot water hurried along the pipes. Then of course it can get screaming hot soon enough and I have to adjust the valve in the middle of what I’m doing.
So the hack I have in mind is to install a mixer valve that is intended for showers. It can be installed under the sink with the output of that going to the hot input of the faucet. Then when I put the faucet on full hot, it opens the hot input 100% just until the preset temp is reached, at which point adjustments are made automatically and instantly. This would give warm water as quickly as possible. If I really need screaming hot water for some reason, the mixer under the sink can be put on full (although I think I have to accept that those probably still have an upper limit).
I feel your are over complicating things a tad. Recirc your hot water from the farthest tap back to the heater. Downside is you heater runs more
https://www.builditsolar.com/Projects/Conservation/Recirc/RecircEnergy.htm
I appreciate the suggestion but that luxury option sounds way more complicated. Adding a thermostatic mixer under the sink needs no pump or electrical wiring, and does not need a third water pipe to go from the faucet back to the boiler. It’s just plumbing under the sink. And in my case, I happen to have spare thermostatic shower mixers so I would just be buying a couple fittings.
I would perhaps even sooner put a small electric tankless water heater under the sink, which would require just one water pipe rather than 3.
I think there’s even a compromise where an electric insti-heat gadget can be plugged into the hot water line to give instant hot water, which I assume shuts off when the hot water actually comes.