Word on the street is, the Power-Pipe Drain Water Heat Recovery (DWHR) System created by RenewABILITY Energy could reduce your water heating costs by as much as 40%. By recapturing significant amounts of the heat that is lost with the used hot water, you could see a significant reduction in your bills.
The system is designed to use the outgoing hot water in the drain pipes to preheat the cold water that is headed into the water heater, raising the incoming water temperature as high as 75°F, greatly reducing the energy needed to heat the water.
“Water falling down a vertical drain stack does not run down the middle of the stack, but instead clings to the inside wall of the pipe. In a DWHR application, falling drain water forms a thin film that rapidly imparts its heat to the colder pipe wall. The Power-Pipe® captures much of this heat, then ‘recycles’ it to raise the temperature of incoming cold water.”
Image Credits: RenewAbilityEnergy
For the fate of the sons of men and the fate of beasts is the same; as one dies, so dies the other. They all have the same breath, and man has no advantage over the beasts; for all is vanity. - Ecclesiastes 3:19