ThermoDrain drain water heat recovery for your home


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.




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The ThermoDrains simple design consists of a single 3/4" copper potable water tube wound around a central copper drain tube.

The ThermoDrain replaces a section of your vertical drain stack. (Lengths vary from 12" to 100", 42" is the most common length)

Wastewater (from your shower or other source of wasted heated water) flowing down the drain transfers heat to the inner drain tube of the ThermoDrain. At the same time, cold water is flowing in the outer coil trying to cool down the warm drain pipe. A heat exchange takes place. The cold water in the coil extracts the heat energy from the drain pipe.

The preheated water in the coil feeds the water heater and/or the cold side of the shower. The water heater uses less energy because it is now receiving preheated water instead of cold water. For tankless hot water heaters, this means a significant increase in the flow of hot water. For tank hot water heaters this means up to 3x more hot water for showering. 

In the shower, you are now mixing warm water with hot water and therefore use less hot water in the shower.

Overall saving is up to 40% on the cost of heating water.

The single coil design offers very low pressure drop and high efficiency and zero maintenance. 





Reduced Energy Consumption

  • Captures some of the heat from wastewater primarily from showers.
  • Reduces demand on energy infrastructure.
  • Provides more hot water for same amount of energy purchased.

Reduced Energy Costs

  • Reduces utility bills.

Reduced Environmental Impact

  • Reduces pollutant emissions associated with fuel-fired water heaters or electricity generation for electric water heaters.
  • Reduces depletion of non-renewable fuel resources.
  • Extends the life of the water heating elements or burner.


  • 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.
  • A ThermoDrain unit consists of copper pipe tightly wound around a vertical section of copper drainpipe. As water flows down the drainpipe, it clings to the inside surface of the drainpipe. The heat from the drain water is transferred through the copper drainpipe to fresh cold water flowing in the outer copper coil.
  • The warmed water is then sent either to the hot water tank or other permitted end-use. In either case, the amount of energy needed to provide hot water is reduced. ThermoDrain systems provide greater potential for energy savings as the number of simultaneous flows increases.
  • ThermoDrain units vary in terms of pipe size, orientation of the drain line, heat exchanger design, cost and energy savings achieved.
  • Water heating accounts for 20 – 25% of the total energy consumption in a typical home, DWHR units can reduce hot water requirements for showering by 40 to 60%

Design/Installation/Operation/Maintenance Considerations

  • ThermoDrain units are available in lengths from 900 to 3050 mm (36 to 72 inches) and two diameters: 75 or 100 mm (3 or 4 inch).
  • What Length ThermoDrain can I install? How do I determine if it is going to fit?: For a xx" long unit, you have to cut out xx" + 0.5" from the ABS drain pipe, to fit the drain couplings you will need 1.25" of ABS at bottom and 1.25" at the top. So for a xx" long unit you will need a minimum of xx" + 2.5 + 0.5 = xx" + 3.0" of straight ABS pipe to work with as a minimum - this is considered a tight fit and requires straight cuts. example: TD342B requires a minimum of 45 inches. A length of 47 inches is preferred.
  • A ThermoDrain unit can easily be retrofitted into existing vertical drains or included in new construction projects.
  • According to Natural Resources Canada-sponsored research, one of the most effective model is the 75 mm (3 inch) diameter, 1500 mm (60 inch) long unit. The most common unit used today in new home construction is the TD342B 3" drain diameter x 42" length.
  • There are generally three ways to plumb the units: directly to the hot water tank, or — where permitted by building codes and regulations — to the shower feed (to preheat the cold water) or to both of these simultaneously for maximum efficiency.
  • If showers all drain to one drain pipe, the savings will be more substantial. If showers do not drain to one drain pipe, each downpipe that carries wastewater from a shower could have a ThermoDrain unit installed. Alternately, one unit can be installed on the drain pipe that serves the shower that is used the most.
  • Most cost-effective for households with three or more occupants who use the shower more often than the bathtub.
  • Does not require special equipment or tools for installation when ordering with the optional CopperLoc fittings. Drain couplings are also included with each unit.
  • Has no moving parts and no special maintenance requirements.

ThermoDrain - 3 simple installation options

In a new construction, the preferred installation configuration is to send preheated water from the ThermoDrain to the water heater's cold supply and to the cold water supply of the shower because it provides the most energy savings.  In renovation projects, often limited access to the bathroom plumbing or the water heater makes it more practical to use the other two configurations as shown below.


The comfort of almost endless hot water is here! The ThermoDrain is perfectly suited for high flow multiple shower heads, rain showers or wall mounted body spray's as it offsets the high running costs of these devices.

Yes, you will save money and reduce your overall energy consumption but what is really interesting about this technology is that it recycles energy. A constant recycling of waste heat energy means longer showers on the same tank. A 40 gallon hot water tank gives you roughly 28 minutes of continuous shower time. Add the ThermoDrain into equal flow and you will get a roughly 90 minute continuous shower or 3X more shower time while reducing your hot water bill by up to 40%*. This test was done at the Canadian Center for Housing Technologies in Ottawa.

*Hydro Quebec estimates



The ThermoDrain will introduce warm water to the water heater from the ThermoDrain and increase the flow rate when showering. When you are using hard cold water, the ThermoDrain will increase the life expectancy of your heater by reducing scalding that causes calcium build up in your heater. You can now enjoy much more hot water and enjoy a long lasting hot water heater.



As a homeowner, you may be interested to know that hot water is the 2nd highest energy user after home heating. Growing energy costs requires that we stop wasting precious heat down the drain.  The ThermoDrain is the most cost effective way to save on utility bills year after year, while adding value to your home. On average, 20% of a homeowner’s energy bill is from heating water. 

If replacing you standard shower head with an ultra low flow model is what you had in mind but fear the lack of flow from these, consider that a ThermoDrain will provide the same energy savings without having to compromise.

Some Technical Stuff

How much of an temperature increase will I see using the ThermoDrain?

Scenario 1
TD342B 42.8% efficient
Drain water temperature 100 F
Cold water temperature 50 F
DELTA T = 50 F
Temperature increase = 50F x 42.8% = 21.4F
50 F cold + 21.4 F ThermoDrain increase = 71.4 F ThermoDrain exit

Scenario 2
TD360B 51.5% efficient
Drain water temperature 100 F
Cold water temperature 50 F
DELTA T = 50 F
Temperature increase = 50F x 51.5% = 25.75F
50 F cold + 25.75 F ThermoDrain increase = 75.75 F ThermoDrain exit


With no moving parts or seals, no required maintenance, and a ten year limited warranty, the ThermoDrain ensures piece of mind, efficiency and savings.



As we take conscience of our environment and the effects we have on it, we all want to play a role in sustainable development. Innovative solutions such as the ThermoDrain will reduce a home’s carbon footprint by one ton of CO2 per year, the equivalent of what one acre of pristine forest can remove.

The ThermoDrain is also the perfect complement to your home’s water heating system. Combined, they offer very high energy efficiency and significantly reduce your home’s environmental impact.  The ThermoDrain is 100% recyclable and is an environmentally responsible product.


99.9% of energy efficient homes use the TD342B.  The TD342B gives the optimum performance and savings versus investment. Most energy efficiency building standards recommend that a drain water heat recovery be at least 42% efficient. You may select your model from the following table.  Your selection should take into account the available length of the 3” drain pipe where the unit will be installed as well as the efficiency you wish to obtain.  The models proposed are all suited for residential installation and should be located on the vertical drain stack that services at least one shower and most of the appliances using hot water.


Note: We do offer the ThermoDrain in metric sizes. 110 and75mm drain diameter x 22mm coil for countries that are currently using metric standard pipe sizes. The drain couplings supplied are also metric compatible.


The ThermoDrain is installed vertically on the main drain stack in order to capture most of the hot waste water used. The preheated potable water from the ThermoDrain may be fed in a variety of configurations to either or both the water heater and cold side of the plumbing fixtures using hot water. No maintenance is required, it has a very low pressure drop and has been designed with outstanding efficiency. The ThermoDrain is easy to install and takes no more than 45 minutes with some plumbing experience.



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