The ThermoDrain is a Drain Water Heat Recovery System (DWHR). It recovers heat from water that would otherwise be lost down the drain. It works best with simultaneous flows like showers, where there is a demand for hot water at the same time as hot water is going down the drain. The recovered heat can be used to preheat cold water going to the hot water tank or for other purposes permitted by codes and regulations. Designed and built in North America, the ThermoDrain is certified to CSA B55.2 and verified to CSA B55.1