Hydronic towel warmer

[wrbix]

Runtal makes great electric towel warmers, but in my current remodel exploring the possibility of hydronic. Have a non-closed-loop hot water system. Other than the initial warm up time and lack of efficiency, why couldn't a hydronic towel warmer be used in the branch running to the shower ? - just warms up when shower runs, which is really the only time warm towels are desired.

 

[Plumber69]

Would never work. You would have to custom build one and take a really long shower. Real long.