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Tankless Water Heaters
Our Gas tankless water heaters are great for everything from a seldom-used vacation home, to the main water heater in a home with multiple showers, or even commercial applications such as a laundromat or carwash. Our current line of tankless water heaters consists of 4 different models: PHH-32 (Condensing, High Efficiency), PH2-28 (High Capacity), PH2-25 (Medium Capacity), PH2-20 (Small Capacity).  Each unit comes in either a direct vent indoor model or an outdoor model.  All of our tankless water heaters can be used with either Natural Gas or Propane.

Commercial Applications

All Waiwela tankless water heaters, except the PH2-20RDVS and the PH2-20ROF, can be converted for commercial use with the simple addition of a hi-temp computer chip. Find out more here.

Direct Vent vs Outdoor

What’s the Difference?

Direct Vent Indoor (Fan Assisted Sealed Combustion)

  • Combustion air is supplied to the gas burner directly from the outdoors.
  • The heater itself has a sealed cover and does not use any air from the space where it is installed.
  • One concentric pipe (pipe within a pipe) opening, run from the water heater through the wall or roof of the home; for exhaust and fresh air intake.
  • Used where tight construction may cause various appliances to compete for the same air.
  • Can be vented vertically or horizontally.


  • Water heater receives combustion air from the environment around it and expels exhaust the same way.
  • We recommend these models for warm climates only.
PH2 Direct Vent Indoor Tankless Water Heater PH2 Outdoor Tankless Water Heater

Gas Tankless Water Heater Comparison

PHH-32 PH2-28 PH2-25 PH2-20
Temperature Range 85°F – 140°F 100°F – 140°F
Gas Input Max (BTU) 199,900 180,000 150,000
Gas Input Min (BTU) 11,000
Energy Factor 0.94 0.82
Dimensions-Indoor Models (W x H x D) 18 1/2″ W x 27 1/2″ H x 9 3/4″ D 13 7/8″ W x 23 5/8″ H x 9 7/8″ D
Dimensions-Outdoor Models (W x H x D) 18 1/2″ W x 27 1/2″ H x 9 3/4″ D 13 7/8″ W x 23 5/8″ H x 8 7/8″ D
Weight 81 lbs 54 lbs
Gas & Water Connections 3/4″ MNPT
Venting (Indoor Models) PVC Pipe 3″/5″ Stainless Steel Concentric Required
Remote Controller (UMC-117) INCLUDED
Warm Climate Performance        
Cold Climate Performance (indoor only)        

represents a single major use, like a shower.