clipped from www.worldchanging.com

That's Hot: EcoDrain Recovers Waste Heat

You've probably heard the saying "like pouring money down the drain." Well, the innovators at EcoDrain say that's exactly what you are doing every time you take a shower -- unless you have installed their high-performance water heat exchanger, that is.

The EcoDrain device (the little gray rectangle in the illustration) circulates heat from your "used" hot water, and transfers it to the incoming cold water. Here's how it works: when you turn on the shower, hot water comes from your storage tank and cold water comes from the municipal supply. As you shower, the "waste" water is sent through a drainage pipe. EcoDrain is attached to this pipe, and transfers heat from the hot water to the incoming cold water supply. Hot water and cold water rush past each other separately inside the device to prevent mixing. Bottom line: the water will be warmer without you needing to turn up the heat.