NETZERO (57.2% efficiency) ThermoDrain TDH3620B-DR-PEX high performance drain water heat recovery unit – factory installed PEX fittings + Free shipping*



The TDH3620B-DR-PEX is the most widely used unit for residential applications next to the TDH3620B-DR due to the simplicity of installation with factory installed PEX fittings.

TDH3620B-DR-PEX  Specifications:

  • 57.2% Efficiency @ 9.5 L/min (2.5 GPM)
  • When showering, a 57.2% efficient unit is designed to preheat incoming cold water from 50 F (10 C) to 78.6 F (26 C) @ 2.5 GPM (9.5 L/min)
  • No Soldering required, comes with factory installed crimp PEX fittings (certified to CSA B137.5 and ASTM F1807)
  • 3″ inner drain diameter
  • 62.0″ Length
  • 10.7 kW Heat Recovery
  • 32.4 lbs
  • Equipped with 2 drain couplings
  • Efficiency verified to CSA B55.1
  • Safety certified to CSA B55.2
  • Download TDH specification sheet

Netzero / Passive house ThermoDrain (57.2% eff) TDH3620B-DR-PEX series

ThermoDrain is an easy and comfortable way to save money and help the environment

The ThermoDrain TDH3620B-DR-PEX series is the latest technology in Drain Water Heat Recovery. Its unique compact design provides high efficiency and an easier
installation. With its exclusive features, the ThermoDrain™ TDH series is simply the best technology available today!

ThermoDrain technology is recommended by the United States Department of Energy, Manitoba Hydro and Hydro Quebec

Code required in all new home construction in Manitoba and Ontario, Canada.

Click Here to view the Specification Sheets

Click here to view Installation guide

ThermoDrain TDH3620B-DR-PEX Model benefits/ features

  • Enjoy hot showers with peace of mind for the environment and energy costs
  • Feel the heat by triples your tank hot water heater capacity for showering
  • Built with the thickest and purest copper for safety and longevity
  • Safety first with double third party certifications for potable water and efficiency.
  • Enjoy significant flow increase on tankless hot water heaters.
  • Quick payback, great return on investment
  • Compact design/ lightweight
  • Maximum efficiency per inch / cost
  • Easy and fast DIY installation with 2x factory installed PEX fittings
  • Includes easy to install drain fittings
  • 50% efficient units are capable of preheating cold water from 50 F to 75 F @ 2.5 GPM
  • Low pressure drop
  • Fits onto any 3″ drain piping system
  • Fits into any 3/4″ potable water type piping





drain water heat recovery pricing



Drain water heat recovery benefits