Discover drain water heat recovery with ReTherm
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Drain Water Heat Recovery
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ReTherm heat recovery technology
Here's how it works

The concept is simple. As warm/hot drain water flows down the vertical heat exchanger it clings to the surface of the inner section forming a very thin film of water. This thin water film allows for ultra-high heat transfer. Heat that was normally wasted now instead is rapidly absorbed by cold water flowing through the outer section.

The preheated freshwater exiting the heat exchanger then proceeds to the conventional water heater. This preheating of the water before it enters the water heater substantially reduces the energy/fuel used by any water heating system.

High Performance Heat Recovery: Decade after Decade

The last thing anyone needs is something new to keep clean. That's why ReTherm is specifically designed to never need cleaning. Many types of heat exchangers require cleaning to maintain top performance, but not ReTherm. The fast moving water on the vertical center section continually scours the heat transfer surfaces. This prevents build-ups that would otherwise rob performance. With ReTherm it's all about lifelong, hassle free heat recovery.

ReTherm water temperature boost
Benefits: More than just energy savings

ReTherm delivers more than just energy savings to the residential and small business sectors. It's an elegant solution with no drawbacks.

  • High heat recovery: up to 60%
  • Easy to install
  • Absolutely no maintenace
  • Zero space required
  • Stay clean design: no cleaning required
  • No power required
  • 100% silent: no noise
  • 100% safe
  • Super long life: 40 year design life
  • Meets all codes
ReTherm works with every type of powered water heater

Regardless of what type of "powered" water heater is used ReTherm significantly reduces domestic water heating costs. Whether using:

  • Electric water heater tank
  • Hot water tank: oil, gas, or propane fired
  • Tankless water heaters: electric or gas-fired
  • even solar water heaters

All water heating systems run less and use less energy when using ReTherm heat recovery. With ReTherm lower water heating costs are a sure thing whether bills arrive from the local oil supplier, the propane guy, the natural gas or the electric company. By putting a stop to needless energy waste you win and the environment wins too.

Heat Recovery from multiple locations
A common misconception about water travelling through drainlines is that it quickly losses heat. The truth is little heat is actually lost, even when travelling over 100 feet. That's why a single ReTherm unit can effectively save heat energy even when there are several hot water usage locations within a home or building.
Going green is easy with ReTherm
Recognition continues to grow for hot water heat recycling technology. The performance of thin water film drain water heat exchangers has been confirmed by various organizations:
  • US Department of Energy
  • Canadian Office of Energy Efficiency
  • and independent university studies


ReTherm heat recycling goes by several names: hot water heat recycling,
drain water heat recovery, grey water heat recovery, waste water heat recovery & shower water heat recovery.
ReTherm stops the #1 waste of household energy
Copyright © 2004-2008 ReTherm Energy Systems Inc.