Use the cold water line as a recirculating loop to save the cost of adding more plumbing
In cold climates—and big houses—it can a minute or two for hot water to reach the sink or shower after turning it on.
This wastes a lot of water and pours money down the drain. One solution is some sort of recirculation pump or system, such as the one illustrated in this video.
Here's how it works:
An internal or an external pump pushes water from the water heater through the plumbing lines at scheduled intervals, or on demand by pushing a button or using motion sensors at the faucet.
In the video, recirculation is accomplished with a dedicated return line.
That’s great if your home has one but many homes don’t have a built-in return line. Adding one can be pricey and time-consuming. One way around that obstacle is to use the cold water line recirculate water between the heater and the sink.
