Down the drain!

One source of heat that we often forget about is the waste heat from the hot water that we use in our house. This "extra" heat can be recovered very easily and put back to use to reduce our energy requirement for heating. One system uses a simple coil-over drain pipe to recover wasted heat.


As the water goes down the drain, it coats the inside of the stack and transfers the heat to the incoming cold water on it's way to be heated. This system works great for end uses that use water as it is draining such as a shower. It does not however work if you are taking a bath as the waste heat only occurs at the end of the fill cycle, not during.


The best way to recover heat from a bath, or if you don't have a recovery heat stack, is to leave the water in the tub until the temperature has equalized with room temp. Of course, you only want to do this during the heating season as otherwise you would be taxing your A/C unit (if you have one). A second benefit of this is the additional humidity this provides during the "dry" season.