Through some quirk of my house's plumbing, I can't get anything hotter than a mild "warm" out of sink faucets. Showers are fine, just not sinks - three plumbers have looked at it and given up. So my question is, does the water used for the brush and lather need to be hot hot? I wonder about it because I can't seem to get a lather that lasts very long (though I am slow), and the brush cools very quickly, enough so that when I re-lather I have rinse and start from scratch with the brush because the water on the brush is now cold.

Thanks!