Here is an "under sink" re-circulation device, instead of the "whole house" approach. Basically, put a thermocouple, solenoid-driven valve, small pump, and a c

Here is an "under sink" re-circulation device, instead of the "whole house" approach. Basically, put a thermocouple, solenoid-driven valve, small pump, and a coupling between the hot and cold water supplies in an under-sink cabinet at (usually) the most remote lavatory sink in the house. When hot water is wanted, the pump pushes cooled water from the hot side into the cold side, and eventually out into the hot water heater's cold water intake. The same flow at the pump pulls hot water from the heater to the sink, and the pump shuts off and closes the connecting valve when hot water arrives at the connection. No water lost, no re-circ except when wanted. Use the sink to set-up to bring hot water near to the shower. Locate or repeat as needed if you have multiple "cold" bathroom or kitchen locations. The reverse flow thru the cold water piping is, uhm, counter-intuitive, but appears to work. https://www.amazon.com/Laing-LHB08100092-AutoCirc-Recirculation-Timer/dp/B0046MDAK0 https://www.amazon.com/Laing-LHB08100092-AutoCirc-Recirculat...