Drain water heat recovery - Récupérateur de la chaleur des eaux de drainage

Drain water heat recovery (DWHR). ThermoDrain is a drain water heat recovery unit that recovers energy from waste water and transfers this energy to potable water before entering a water heater. It is different from other heat exchangers in that it has dual walls vented to the atmosphere so that cross contamination between wastewater and potable water is not possible. The heat transfer occurs only when wastewater is flowing down the drain while there is a demand on the hot water heater. This technology can save the homeowner up to 40% on their water heating bills. It can also triple the capacity of a hot water tank for showering. It is considered a comfortable green technology designed for shower lovers who also want to save energy. ThermoDrain is a superior drain water heat recovery technology that is manufactured in North America and comes with an industry leading 10 year warranty.


ThermoDrain, A Unique Drain Water Heat Exchange Technology

The ThermoDrain drain water heat recovery unit is composed of a copper drain section around which a copper pipe is moulded and wound. As hot water drains down the central copper pipe, an important heat transfer occurs thereby preheating the cold water circulating in the outer coil. This incoming cold water may be preheated by more than 18 degrees Celsius (32 degrees F) before entering the water heater.

ThermoDrain™ drain water heat recovery exclusive 3/4" single coil design

What makes the ThermoDrain so unique is that it is the only style of heat exchanger that is allowed to be used for potable water due to its double wall leak proof design. 

The ThermoDrain is the only drain water heat recovery unit that has a very low pressure drop through the use of a single 3/4" coil. Other manufacture designs require splitting of the flow into 1/2" or 3/8" thin walled channels and headers. Designs that do not improve performance but may impact longevity of the unit. 

ThermoDrain's is constructed using potable copper tubing with walls that are 0.045" thick and a 0.75" in diameter


Clogging of the ThermoDrain is not possible like other heat exchangers. 

 The ThermoDrain does not have restrictions such as fins inside of the drain pipe.

The ThermoDrain does not have restrictions such as fins inside of the drain pipe.

The Physics

heat recovery unit english FINAL.png

The ThermoDrain heat exchanger works under the principle of gravity film exchange. Due to the superficial tension present in liquids, the waste water clings in a film-like fashion to the inside wall of the drain pipe as it undergoes gravity flow in the open drain. This greatly improves the effectiveness of heat transfer from the falling drain water to the water inside the copper coils that winds around the central pipe. The heat exchange is thus completed with no contamination risk to the incoming cold water.

A superficial film forms on the interior wall of the ThermoDrain as hot waste water transfers its heat energy to the copper drain tube.

Specification Sheets