Rinnai Boilers RC80/RC98 
Review and Buying Guide

Rinnai boiler

A review of Rinnai boilers utilizing the condensing technology for combined whole-house space and water heating. Explore Rinnai condensing boilers features and the advantages.

A Rinnai condensing boiler is an ideal solution for the homeowners who want to use only one heat source – gas, for both residential water and space heating. These gas boilers are designed small but powerful that can provide extra efficient heating and offer not only the optimum comfort but economical and convenient heating.

Models review

Several Rinnai boilers utilize condensing technology and are designed for different home sizes; from small to large. The smallest condensing boilers from Rinnai come with the max. gas input of 75,000 BTU while the largest one offers the maximum power of 205,000 BTU. All models are ultra efficiency models with the high EF factor which makes them Energy Star qualified.

Gas input
Efficiency Water flow (GPM)
Q205S 205,000 95.7 Indirect tank
Q175C 175,000 95.7 6.2
Q130S 130,000 96.1 Indirect tank compatible
Q175S 175,000 95.7 Indirect tank compatible
E110C 110,000 96.1 4.6
Q85S 85,000 96.5 Indirect tank compatible
E75C 75,000 96.5 2.1

Buy the Best of Rinnai

As you can see from the above table, there are two series you can choose from; Rinnai Q and E series.

Rinnai Q series is designed for homes with the higher hot water demand and larger families, and Rinnai E series is ideal for families with smaller hot water needs, or smaller houses, apartments...

Models Q172C, E110C, and E75C are combi boilers for heating and domestic hot water (DHW) while other models are for space heating and optional DHW.

Q172C model is the only model from Rinnai Q series that comes with the indirect water storage tank while other boilers can be connected to the indirect tank and provide hot domestic water also.

All the boilers are equipped with the water pump, and if an internal 3-way valve is installed on "S" system models, there is no need for a pump to run the water through the indirect tank.


  • All the boilers are high efficient (Maximum AFUE efficiency is 96.5% while the minimum is 95.7%), making them Energy Star qualified while providing significant savings.
  • Compact size provides space-saving installation.
  • Ideal for new homes while they can be simply retrofitted to replace the old tank-type models.
  • As the tankless water heaters, Rinnai boilers are also wall-mounted.
  • All Rinnai condensing boilers are equipped with the durable and reliable stainless steel condensing heat exchanger.
  • All the boilers are designed to work on both natural gas and propane gas where the conversion kit is used to convert one fuel type to another.
  • Variety of venting options is available for the flexible installation. Every Rinnai condensing boiler can use PP, stainless steel, PVC and CPVC venting.
  • There are more benefits if the RS100 controller is connected to the boiler. You will have access to the programmable features, temperature control, error reporting, and auto-service message.
  • Modulating burner.
  • Rinnai Q172C includes a 6.6-gallon tank with the built-in thermostatic mixing valve.
  • Direct vent sealed combustion allows Rinnai boilers to be approved for room and closet installations.
  • Rinnai gas condensing boilers are ASME (American Society of Mechanical Engineers) certified, so they meet relevant safety specifications.
  • Boilers are equipped with the outdoor sensor making them weather dependent.
  • Both Rinnai Q and E series are equipped with the electronic spark ignition which automatically lights the burner (no pilot light).
  • At the front of the unit, there is a control panel which is consisted of the display and function buttons. The display shows the boiler status, error, and maintenance messages while the buttons have control over the pump, central heating, domestic hot water heating, and service modes.
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The main disadvantage is that Rinnai boilers are expensive.


Rinnai boilers are expensive, but they offer premium quality of its components and ultra-efficient condensing technology, so the heating of your home and domestic water is economical and reliable. These superb devices are packed in a small and compact tankless design that doesn't occupy valuable living space - they are wall-mounted that can be installed almost anywhere.

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