Wasting energy is not a wise idea. Even if you don’t care about the environment, you certainly care about the money in your pocket. EcoDrain happens to be an interesting creation that helps you save money in the shower every time. It transfers heat energy from your waste water to the incoming fresh water. Waste water never comes in contact with the fresh water supply, but its energy lets you take longer hot showers without hurting your pocket.
EcoDrain is available for under $440 at the time of this writing.