Huh? Regular thermostatic valves do not provide perfect regulation but they do in fact provide a fairly stable output temperature regardless of cold and hot water temperature, by entirely mechanical means. I have a cheap IKEA shower control and output temp is stable for the full duration of my shower even though cold nor hot water supply is stable due to a shower drain heat recovery unit.
The article is mainly about wanting the regulation to be between 35-45C instead of 15-55C.
The article is mainly about wanting the regulation to be between 35-45C instead of 15-55C.