Instant hot water recirculating pump (Home Depot or COSTCOMischoses.
Since re-locating the water heater, it took about 3 to 5 minutes to receive hot water in our two bathrooms. The pump is activated by a temperature sensor attached to the hot water line. When the line cools below 100 Degrees F, water from the hotwater line is pumped into the cold water pipe under the sink. Now there is warm water almost instantly, and hot water in about 30 Seconds. Although the pump has a built in timer, I control on/off periods with the home automation computer (Home Vision Pro). The after pix is of the X-10 control module. This method allows us to shut the pump down when we are not home. In the future I plan to install a motion detector in both bathrooms so that hot, rather then warm water, will be available instantly. I installed an electrical outlet under the sink rather than cutting a hole in the cabnet and routing the power cord to the existing outlet