All the right choices.

No matter which Eternal you choose, you'll get endless hot water, consistent pressure and never a cold water sandwich. When installed in optional recirculation, you'll save water by never waiting for hot water again.

The Future is Here - 98%+ Efficient - Eternal Hybrid™



  • All Stainless Steel Heat Exchanger with built-in 2 gallon reserve tank
  • Meets NSF Standards for health and cleanliness
  • Ultra low emissions (1ppm CO) leaves almost no carbon footprint and is safe
  • Patented self-cleaning utilizes turbulent flow to flush sediments out


  • 98%+ Efficiency saves cost, exceeds Energy Star standards
  • Compact chassis can wall or floor mount; standard water connects on top
  • Dual Core CPU displays error codes and optionally controlled by up to 3 remotes
  • Clip-on components can be easily serviced by technicians


  • Full flow design enables high output without water pressure drop
  • Thermostat and Flow Activation is compatible with WaterSense fixtures
  • Easy integration with recirculation and no startup lag eliminates cold water sandwich
  • Meets UL / CSA / ANSI / NSF and UPC standards
  • 15-year residential and 5 year commercial Heat Exchanger warranty

Models and Features

Eternal Water Heater

GU145 (S)3

  • Up to 14.5 GPM of unrestricted flow
  • 145,000 BTU's Max Input
  • Great for up to 3 simultaneous residential applications
  • Copper internal piping connections
  • Available S Option Factory Installed All Stainless Steel internal piping connections

GU195 (S,M)5

  • Up to 19.5 GPM of unrestricted flow
  • 199,000 BTU's Max Input
  • Great for heavy residential or light commercial applications
  • All Stainless Steel internal piping connections
  • Available M Option Factory Installed Multi Control Unit module for up to 8 GU195M in network for heavy commercial

Download the Eternal Hybrid Spec Sheet for details

The Original Eternal Hybrid™



  • Consistent water pressure even with multiple taps in use
  • Compact yet capable of replacing multiple tanks
  • Compatible with recirculation to deliver hot water quickly without wait
  • Faster hot water delivery than competing tankless units


  • High efficiency maintained with patented self cleaning
  • Ultra low emission as low as 3ppm NOx to reduce carbon footprint
  • Pre-Mix full modulation infrared burner precisely matches fuel usage to demand
  • Easy installation with 2" or 3” approved PVC venting
  • Convertible to LP with optional kit


  • All stainless steel construction is durable and clean
  • Computer controlled mixing valve and multiple sensors ensures precise water temperature
  • Digital display is easy to set and displays errors for simple troubleshooting