Rinnai RL75iN & RL94iN Natural Gas Tankless Water Heater Review


Reviewed by:
On October 29, 2015
Last modified:October 5, 2016


“Another Versatile Natural Gas Tankless Water Heater” 

With so many tankless water heaters on the market, how can you be sure that you’re buying the right model for the right price? Between BTU, GPM and other strange acronyms, you might not know which way to turn.

The good news is that the Rinnai RL94iN / RL75iN will put these questions to rest. If you’re looking for the best natural gas tankless water heater on the market, your search can stop here.


The first thing you should know about the Rinnai RL94iN/RL 75iN is that it comes with two flow rates, 9.4 gallons per minute and 7.5 gallons per minute respectively. Larger homes will need the former; smaller homes might only require the latter.

There are also slight differences in their BTU:

  • The 9.4: 9,900 – 199,000 BTU
  • The 7.5: 10,300 – 180,000 BTU

You’ll find differences in the physical size of the heating unit, too:

  • The 9.4: 50lbs, 9.3 x 14 x 23″
  • The 7.5: 45lbs, 14 x 9.3 x 23 “

Aside from these figures, however, both models come with the same functions and features. For example, they both have 82-83 percent thermal efficiency, and their residential control settings range from 98°F – 140°F. Commercial settings can climb to 185°F.


If you don’t already know, natural gas tankless water heaters work by heating cold water as it passes through your pipes. Internal sensors detect when cold water needs to be warmed, and natural burners trigger a heat exchanger that will get your water to just the right temperature before sending it through the tap.

The Rinnai RL94iN follows this process to a tee. Furthermore, it’s known as a “workhorse” brand around the market, meaning that it’s the kind of tankless heater that people install and then forget about because it functions so quietly and efficiently.

The 9.4 model can handle up to five bathrooms at a time; the 7.5 model can handle between two and three.

You won’t have to worry about simultaneous usage with this heater: You can take showers, run dishwashers and even do your laundry at the same time.

Heat Output and Flow

The heat output of the Rinnai RL94iN is quite impressive. In a residential home, you can make your water as hot as 140°F; in commercial settings, this figure climbs to 165 – 185°F. You may or may not need a special controller to unlock these temperature settings.

The flow rate is another plus. Like it says in the name, the 9.4 model can pump more than nine gallons per minute throughout your home, which is enough to comfortably serve multiple bathrooms and appliances.

Customers do report slight (~30 second) flow delays when using the Rinnai RL94iN. They say it needs a moment to “boot up” for the day. Once it’s going, however, the hot water won’t stop, so it’s a small sacrifice for unlimited hot water.


One drawback of the Rinnai RL94iN is that it needs to be installed very carefully. This is true of all natural gas tankless water heaters; since they use open flame that produces emissions, you don’t want to cut any corners when it comes to pumps and vents. Many buyers just leave the installation in the hands of a certified Rinnai technician.

You might need to run a second gas line to accommodate this model. It depends on the demands that your current gas line can handle.

Vent kits and valve kits can be ordered with the unit.

General Use

As with any decision, you should look at the pros and cons of a tankless water heater before ordering. Here are a few of the basics:



  • Serves multiple bathrooms simultaneously
  • High flow rates are perfect for large homes
  • Can be converted to propane if you don’t like natural gas


  • Slight (~30 second) flow delays at the tap
  • GPM decreases as water temperature climbs
  • System requires careful installation with many bells and whistles

Customer Reviews

On the whole, customers report being very satisfied with their purchase of a Rinnai RL94iN. There are some complaints about the nitty-gritty details of installation, and a few users aren’t happy with the limitations of the heating unit, but generally speaking, customers are pleased with the Rinnai brand and happy that they’ve bought a unit that doesn’t require constant care.

With a Rinnai, simply install it and let it work.

Take a quick look at Amazon to see what others are talking about this product !

The Final Verdict

The 7.5 model handles less bathrooms but also requires less power to operate, so it’s a trade-off.

Despite a few problems, the Rinnai RL94iN is one of the strongest and most worthwhile natural gas tankless water heater on the market. Also the other model ,Rinnai RL75iN would be the most suitable choice for most of them with a lesser price tag . But you don’t have to take my word for it:

Check out both the Rinnai RL94iN and the Rinnai RL75iN model on Amazon to see their specs, reviews and usage details for yourself.

Further Information

Click Here to Leave a Comment Below 0 comments