BruceR wrote:

A better and less wasteful way to do this would be with a Laing
Auto-Circ (http://www.autocirc.com/Autocirc.htm). It easily installs
under the sink in your bathroom and attaches to the hot and cold lines.
When turned on it pumps water from the hot line back to the cold side so
hot water water is always available.


Here in the UK at least this would break the Water Bye Laws and/or
guidelines for prevention of legionaires disease.