Get Twice the Hot Water of a Typical Tank

All In a Quick and Easy Installation

  • 180 gallons of hot water in the first hour – More than twice that of a typical tank water heater
  • Installs like a typical tank water heater – Easy and efficient installations
  • Standard gas, water, and exhaust connections – No need to reconfigure your existing setup*
  • Does the job of more than two typical tanks – Twice the work using the same space as 1 tank

Who is the RH180 for?

The easy installtion makes a Hybrid Tank-Tankless Water Heater perfect for anyone who wants to increase their homes’ hot water capacity without reconfiguring an existing setup.

  • Emergency replacement – can be installed same day
  • Remodeling homeowners
  • Small commercial businesses

htt_installation_szSpace savings.

The RH180 does the job of more than two traditional tanks, which means it can save valuable space within your home or business.

How does it work?

  1. When hot water is used, it exits from the top of the tank while entering cold water is directed toward the bottom.
  2. Sensing the temperature difference, the tankless unit activates, drawing cold water from the bottom, turning it into hot water, and returning it to the top of the tank.
  3. When hot water usage stops, the tankless unit continues circulating the cold water from the bottom and returning it as hot water to the top of the tank until the tank is completely recovered.


With 180 gallons of hot water in the first hour, the Rinnai Hybrid Tank-Tankless Water Heater makes a superbly efficient combination. Installation is simple with standard hookups, while tankless technology works to quickly refill the tank with hot water on-demand. This gives you more than twice the hot water of a traditional tank water heater, and more than enough for your entire family.


  • Hybrid = two technologies
    • Tankless engine:
      • Max Input: 91,300/87,500 NG / LP
      • Min. Input: 59,500/47,600 NG / LP
      • Thermal efficiency: 80%
    • Storage Tank: 40-gallon, blue-zircon glass lined
  • First Hour Rating: 180 gallons (77° rise rating)
  • Dimensions:
    • Height: 51.2” Width: 23.8” (tank: 18.7”) Weight: 150 lbs. (empty)

Capacity Comparison

  First Hour Rating
Comparison of RH180 to other tank products Standard atmospheric tanks
(electric tanks are even lower)
Condensing Tank
40 gallon tank 66 to 81 gallons  
50 gallon tank 80 to 93 gallons 164
75 gallon tank 130 to 131 gallons  
2 Each – 40 gallon tanks 132 to 162  
RH180 180 gallons  
Rinnai tankless (R75 or R94) 258 gallons