Stop heat from going down the drain with the water

Business Week's "Green Biz" editor Adam Aston found this device, but didn't provide the link to the manufacturer. It must work on the same principle as the legs of Arctic terns and other birds that stand on ice but don't freeze: heat exchange. Two pipes (blood vessels, in the case of the birds) close together, one carrying cold up and the other heat down. Each has a temperature gradient, but in inverted relationship to each other, so the actual temperature difference at any point is minimized, and thus little heat need be lost. I learned this principle in theoretical biology class some time ago. Quite some time ago.