Rinnai RUC80iN Review

The Rinnai RUC80iN is one of the flagship models for the Ultra series of condensing tankless water heaters. These water heaters are designed specifically for medium to large size homes and can output hot water at a continuous 8.0 GPM (Gallons Per Minute). Utilizing Rinnai’s technologically advanced condensing technology to maximize efficiency, this model achieves an energy factor of 0.96, quite an impressive feat.

This energy efficiency translate to additional savings as nearly no energy is wasted. With the RUC80iN installed you will never run out of hot water again, while pocketing extra money each year in reduced energy costs. This model outputs up to 130,000 BTUs of heating power and can push out 8 gallons of hot water a minute. This entry into the Ultra series is ENERGY STAR® certified, so you know you are getting one of the most efficient models out there.

The electric ignition within this model cancels the need for a pilot light, saving you even more money in fuel costs.

The Perfect Hot Water Temperature, Every Time

Set the temperature exactly how you desire! No more fiddling around with the knobs in the shower, trying to get that perfect temperature. Simply set the hot water heater to your favorite temperature, and Boom! You are ready to start enjoying the perfect shower every time. There is even a temperature lock feature that prevents unauthorized persons from changing the temperature on the device.

Here is a review from Dion on Amazon, a professional in the HVAC industry:

“Very impressed, I have been in the HVAC/Plumbing industry for over 30 years. I mainly deal with tall buildings that the HVAC/P equipment is ultra critical. When I decided to install one of these in my house I did a lot of research and even attended a training seminar at the local plumbing supply house. In my opinion this was the best unit available.”

He goes on to say that he does not represent Rinnai, and that he normally deals with units 10 to even 100 times bigger than this! Dion continues his review:

“I have only had it going for four months so far and I discovered I needed to add a recirculation circuit to the hot water line. Unlike other water heaters that allow hot water to migrate through the pipes even when not in use. This unit does not, so it took a little while for hot water to arrive at the tap or shower head. All better now.”

As Dion points out, in order to maximize this hot water heater you will need to supply the pump to allow for re circulation, so that is something to watch out for.

According to Amazon, this unit is able to comfortably provide hot water for 2 families. A total of 2 washers, 2 kitchens and 3 bathrooms will handled like a champ by this heater! To directly quote an Amazon answer:

“I can shower in my apartment while my daughter does laundry and my grandson is taking a shower in their bathroom. You will not run out of hot water like you will with a standard water heater.”

Worried about a hot water heater leaking and damaging your home? Put those fears to rest with this Rinnai model that has a leak detection feature, so it is able to shut off the water and limit property damage. It really is a smart hot water heater!

The average review on Amazon for this unit is 4.8 out of 5 stars at the time of this writing, quite an impressive score and well above the average for most tankless water heaters.

My main gripe would be the lack of a recirculation pump, it is a little annoying that you have to purchase one yourself, but it is a very easy installation and you will notice marked improvement in hot water delivery times.


Specifications for the Rinnai RUC80iN :

  • Dimension: 10 x 18.5 x 26 inches
  • Size: Twin Pipe / Ultra
  • Voltage: 120 Volts
  • Flow Rate: 8 GPM
  • Energy Factor: 0.96
  • Fuel Type: Natural Gas
  • Temperature (Max): 140°F
  • Temperature (Min): 98°F