Rinnai RU80i Tankless Water Heater Reviews

Rinnai RU80i Review


The Rinnai RU80i tankless hot water heater is part of the Rinnai Ultra Series. We understand why its considered Ultra after reviewing this tankless water heater. This might be the most energy efficient model we have seen yet, with an EF of .096 and only using 42 watts while on and 2 watts in standby mode, you are sure to save on your energy bill.


This tankless water heater reviewed  is suited for a medium sized household with 3 showers.


What we liked about the Rinnai RU80i

1. This unit supports concentric venting with both vertical and horizontal termination. This allows for one penetration in the building envelope, reducing install time. The vertical and horizontal termination gives more installation options. Instead of having to reline a chimney stack you can run it out the side of your house, saving installation costs.


2. The temperature range is from 98° F-120° F, normal for most tankless water heaters. However, it can be change to run up to 140 °F. While we don’t recommend setting it this high, its nice option incase you need the ultra hot water.


3. For a model with this BTU rating we liked the smaller size of the unit.


4. This is an optional controller which can be used to control the water temperature from a remote location. i.e. master bathroom


5. This hot water heater has the Rinnai Circ-Logic™ built into the unit. This means you can have your plumber hook up a receriltaing pump to always have near instant hot water.


6. Built in leak detection. This will shut off the water to the interior unit, which helps reduce the chance of property damage incase there is a leak.


7. The unit is very quite then most models of this BTU and GPM rating.


8. Direct electronic ignition (no standing pilot lights)


What we didn’t liked about the Rinnai RU80i

No tankless water heater review would be complete without some cons to the unit. Well there really isn’t anything that we didn’t like about it. The only thing we didn’t like is the premium price. However this is a premium product so I think Rinnai is justified in the cost.


Safety Features

Flame failure

Boiling protection

Combustion fan rpm check

Over current fuse

Remaining flame

Thermal overload shut down

Automatic frost protection


Rinnai Gas Tankless Water Heater RU80i Specs:

  • Min Gas Consumption Btu/h – 15,200
  • Max Gas Consumption Btu/h – 152,000
  • Water Capacity GPM Activation – .4
  • Water Capacity GPM Max – 8.0
  • TemperatureRange (With Include MC-91-2US)) – 98 ° to 140 °
  • Max Temperature (With Optional MCC-91-2US Controller) – 185 °
  • Electrtical Consumption (normal) – 42 Watts
  • Electrtical Consumption (stand-by) – 2 Watts
  • Gas Supply Connection – 3/4 inch MNPT
  • Cold Water Input Connection – 3/4 inch MNPT
  • Hot Water Input Connection – 3/4 inch MNPT
  • Weight – 70 lbs