Rinnai V65 
Tankless Water Heaters
Review and Buying Tips

Rinnai V65 tankless water heaters are the second smallest units from all Rinnai appliances. These economy models are recommended mainly for residential water heating in non-freezing climate regions and small and medium-size homes with 2 to 4 bathrooms.

The review leads you through the main features to look for and advanced technology that provides efficient and reliable heating, yet flexible, safe, and comfortable for you and your family.

Note: If you need larger and more advanced models, check out our review of Rinnai RUR98 and RUC98.


Rinnai V65 models review

Rinnai V65 tankless water heaterRinnai V65

Rinnai V65 models are non-condensing and tankless water heaters that bring high efficiency and superior water heating due to their intelligent design. They heat water on demand, continually delivering hot water to one or multiple fixtures saving space, water, and energy. Except for residential homes, V65 models are certified for installation in mobile homes as well.

They are compact, small, and lightweight that do not occupy any floor space but are easy to install on the wall and, thanks to simple commands, use.

There are four models to choose from, which can be installed inside the house or outside, using natural gas or propane gas.

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Rinnai RL75i, as the indoor models, are designed with the sealed combustion and concentric vent-type system using the outside air for combustion safely to remove products of combustion to the outside atmosphere.

Designed as the direct-vent tankless water heaters, indoor models transfer products of combustion horizontally through the single wall and vertically with the roof penetration. They can be installed in any room type.

Rinnai RL75e models come with a ventless design so that they can be installed only outdoors and usually inside a recessed enclosure.

Feature review


Rinnai V65 tankless water heaters are designed with the maximum water flow of 6.5 gallons per minute so they can supply two to four applications simultaneously, making them ideal not only for point-of-use-service but also for point-of-service whole-house heating. If more hot water is needed, you can use the EZConnect cable to connect two indoor models to work as one, but this is optional.

Due to its simple design, V65 models do not have an option for recirculation, but if you require faster hot water delivery, we recommend buying either RUR98 or RUC98 models, they are the best of Rinnai.


An indoor unit V65i is a direct vent water heater with sealed combustion that uses a vent system to bring the outside air in for gas combustion and move the exhaust gases out, making it safe to use inside the home (bathrooms and kitchen).

While an indoor model uses the venting system with horizontal or vertical termination, an outside model V65e doesn't require any venting since it is ventless and mounted outside. It can be installed inside the recessed box for a better look and protection.


Rinnai V65 models are designed to work with the maximum power of 120,000 BTU making whole-house water heating possible. The minimum power they can get is approximately 10,300 BTU which is mainly used in point-of-use applications.

This is possible as the units are equipped with the modulating gas burner, which adjusts the power based on the set temperature and water flow.

A modulating burner ensures consistent temperature with less hot water temperature fluctuation (cold water sandwich) and higher energy savings.

According to the Energy Guide, an estimated yearly energy cost is close to $200 when the natural gas is used and around $480 with the propane.


The temperature controller MC-91-2US is built into the front panel of the indoor model while it is provided with the outdoor unit. The controller offers better control of the outgoing hot water temperature, and by using the diagnostics system, it can display error codes when the problem occurs, making the troubleshooting easier. If the provided controller is used, the temperature can be set between 98 and 140 F, but if you need a higher temperature for the hydronic heating, install the MCC-91-2 controller, which allows you to set it up to the maximum temperature of 160 F.

If the water heater does not use the temperature controller, then the temperature can be adjusted by putting the switch in the correct position.

Every tankless water heater from Rinnai, including V65, is Wi-Fi capable of making remote control and monitoring possible.


Rinnai V65 water heater is continually checking water heating operation. If there is a problem with the heater, the error codes 02, 03, 11, etc., will be displayed on the remote control if installed. If it is not installed, then the error code will flash on the control panel. The error codes will make troubleshooting easier and with the help of a licensed technician much quicker repair.

Safety elements

  • Flame rod - the water heater will automatically shut down if the burner flame goes out.
  • Combustion fan rpm check.
  • Overcurrent protection - if the fuse blows, all the lamps will be OFF.
  • The thermal fuse will break if the overheating feature does not prevent the temperature from rising and shut off the unit.
  • Automatic frost protection.
  • Remaining flame – OHS.


  • The energy factor is 0.82 for both indoor and outdoor units.
  • The temperature setting is from 98-140 F. The units are factory set to 120 F.
  • The heater meets California and Texas NOx emission requirements.
  • Direct electronic ignition instead of the pilot light.
  • Gas and water fitting size is 3/4", which is standard size.
  • Water pressure range is from 20-150 PSI.
  • Certified for mobile and manufactured home installations.
  • Compatible with Rinnai controllers.
  • Hot water capacity is from 0.6 to 5.3 GPM.
  • Warranty is 10 years on heat exchangers for residential and hydronic applications, with an option to increase to 12 years with the installation of the isolation valves.

NoteProfessional installation and repair are recommended. Find local plumbers and get FREE Quotes!


Rinnai V65 is an excellent solution for homeowners who need a reliable tankless water heater that supplies hot water with a consistent temperature, on-demand, and for up to four applications. The high efficient operation ensures better energy savings and reduced heat loss. It is recommended for small and mid-sized houses and budget-oriented families.