Best Rinnai Tankless Water Heaters

Best Rinnai Tankless Water Heaters Reviews [Updated 2019]

Tankless water heaters heat water only when it is needed. They are compact and supply hot clean water to multiple outlets simultaneously without any temperature fluctuations. Many people prefer these units because they reduce water heating bills.  These models have been used for decades, but their popularity has increased only in the past few years.

If you are looking for the best tankless water heater for your household, we recommend you check out the Rinnai units. We love this brand for one major reason: it stands true to its promise of delivering the best quality products. Rinnai is a brand widely-known for their reliability and quality. This Rinnai tankless water heaters review gives you the best selling units from the brand. Hopefully, you will be able to find a model that meets your family’s unique needs.

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1. Rinnai RUC98iN Tankless Water Heaters Reviews

Rinnai RUC98iN Ultra Series Natural Gas Tankless Water Heater, Concentric/Twin Pipe Installation


We begin our tankless water heaters reviews with the RUC98iN Ultra Series. This model is an indoor gas tankless water heater designed for both residential and commercial applications. In terms of size, the Rinnai RU98iN measures approximately 18.5 by 26 by 10 inches and weighs 61.7 lbs. This may be quite hefty, but as opposed to the traditional water tank, the unit is less bulky, so you still come out on top regarding floor space.

  • Maximum size of 199,000 BTU
  • Energy factor of up to .96
  • Allows either concentric or PVC venting
  • Space-saving design

The unit boasts a flow rate of up to 9.8 GPM which is quite a phenomenal number. If you live in the Arctic region, your flow rate can be a maximum of 6 GPM. We love that this tankless water heater gives you hot water instantly. Unlike other models, you do not have to wait for long to get hot water. It serves multiple bathrooms at the same time, and the best of all is that you can place it anywhere in the house. One thing you should not about the RUC98IN is that it comes with a special NOx system.

High efficiency

You don’t have to keep it outdoors because there are no dangerous fumes that build up when you put it in enclosed spaces. Because we are talking about Rinnai tankless water heater reviews, allow us to point out that the RUC98IN model is perhaps the most efficient heater we’ve seen so far. The unit boasts an energy factor of .96 which is quite energy saving. When on standby, it requires only 2 watts as opposed to the normal 64 watts. We give it a 5/5 when it comes to size because you can even install it in crawl spaces or the attic.

Environment-friendly design

There is also a small remote control that you can use to operate the water heater. And with a residential warranty of up to 12 years on the heat exchanger and 5 years on parts, you’ll surely be able to rest easy knowing you’ve put your money in the right place. Overall, we give the Rinnai RUC98iN 4.6 stars. While it is a bit bulky, you can easily operate and maintain this unit. Because it does not store water, there is no chance of getting unwanted residue from the faucet. We know you will love the sleek and attractive design of this unit – it adds a nice touch to your indoor space.


  • Special NOx system makes it safe to use indoors
  • Perfect for both residential and commercial settings
  • Delivers up to 9.8 gallons per minute GPM
  • Can be installed nearly anywhere in your house
  • Quite energy-saving
  • Adjustable temperatures


  • Not the most affordable unit available on the market
  • You may need a trained professional to install it

2. Rinnai RL94i Tankless Water Heaters Reviews

Rinnai RUC98iN Ultra Series Natural Gas Tankless Water Heater, Concentric/Twin Pipe Installation


We take a close look at the RL94i tankless water heater which is part of the brand’s Luxury Series together with three other models. The 199,000 BTU model is designed for indoor installation. It is perfect for residential and commercial applications as well. What we like most about the Rinnai RL94i unit is its size. It measures approximately 9.3 by 14 by 23 inches and weighs only 50 pounds which means one person can easily install it.

  • Propane and natural gas models available
  • Energy star compliant
  • Digital controller with error code indicator
  • Maximum gas consumption of 199,000 BTU
  • Water capacity of up to 9.4 GPM
  • Commercial-grade heat exchanger
  • 97 watts electrical consumption

The indoor tankless water heater can handle up to four fixtures at a time. It also includes valves to make installation easy. The enhanced anti-scale detection reduces the possibility of serious damage to the unit. On standby mode, the unit uses only 2 watts of electricity which is quite energy-saving. The unit’s safety features include automatic frost protection, thermal overload shut down and combustion fan RPM check among other features.

You may want to shop for other options available if you are on a tight budget but we still believe this unit is worth the money. We also love the attractive finish of this unit because it gives your home a nice clean look. The company throws in an exclusive warranty on parts to give you peace of mind when using the tankless water heater. No doubt this unit deserves a spot on this Rinnai tankless water heaters reviews.


  • 83 percent thermal efficiency
  • Space-saving design
  • Error code indicator that lets you know when to flush the unit
  • Flexibility in controlling the water temperature
  • Has direct electronic ignition


  • A bit pricey

3. Rinnai RU98EN Tankless Water Heaters Review

Rinnai RUC98iN Ultra Series Natural Gas Tankless Water Heater, Concentric/Twin Pipe Installation


Our Rinnai tankless water heaters reviews wouldn’t be complete without a sneak-peak of the RU98EN unit. It is among the most powerful tankless water heaters from the brand under the Ultra Series. By the way, this unit is an outdoor natural gas water heater. The sister model of the Rinnai RU98IN is perfect for large families or homes where there is high usage.

  • Maximum energy factor of .93
  • Maximum BTUs of 199,000
  • Outdoor tankless water heater
  • Up to 9.8 gallons per minute
  • Temperature range of between 98 F – 140 F
  • Commercial-grade heat exchanger
  • EZConnect feature
  • Energy star qualified

We love the temperature lock feature built into this unit because it prevents accidental changes to the water temperature. You will also notice an enhanced scale detection feature incorporated to reduce the possibility of serious damage. Like the previous units, the brand has made this model more attractive. The unit also incorporates condensing technology to deliver more efficiency than before.

The Rinnai RU98EN unit is perfect for large families and has enough capacity to enjoy up to five plumbing outlets simultaneously. To operate as a condensing water heater, the unit uses two heat exchangers. The best features of the RU98IN include its energy factor of .95 and hot water capacity of up to 9.8 GPM. According to tankless water heaters reviews online, customers love the RU98EN because it does a great job of supplying hot water simultaneously for three bathroom faucets, a kitchen faucet, and two showers.


  • Temperature controller so you can adjust the temperature manually
  • Two heat exchangers
  • Most efficient model because it is a condensing tankless water heater
  • Great for large families
  • Enhanced scale detection


  • Can be difficult to install

Wrapping up Rinnai Tankless Water

Rinnai tankless water heaters are popular because of their high efficiency and environment-friendly design. You can rely on them for endless hot water supply. These three products are by far the best units by Rinnai, and we say this after evaluating numerous products carefully. Based on our research and the features of the best tankless water heater, we find that the Rinnai RU98EN unit is the best model of the three on our list.

Why is it the best? Well, it has a very high output making it great for medium to large families.  Another good thing is that it frees up interior space and saves on the installation costs. Because it is a condensing model, it is the most efficient and most powerful tankless water heater on this list. Even though it is difficult to install without professional help, we believe that it is still the best tankless water heater worth every dollar you spend.


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