5 Best Rinnai Tankless Water Heater Reviews

Last Updated on April 24, 2021 by Michael

How will you feel about taking bath in cold water during winter? Thanks to the Rinnai tankless water heater that you won’t have to experience such a horrific thing anymore. The tankless water heater is compact, easy to install, and energy-efficient. So, you can easily get hot water without any hassle. The best part of it is that you can get instant hot water, without the need to wait.

Tankless water heaters were first made in Japan in 1920, then it was introduced in the American market. During the last decade, this product has been in use in Asia and Europe for many years.


You will find Rinnai tankless water heaters in various sizes in the market. When you decide to buy this water heater you should consider the capacity, type of fuel (natural gas, propane, or electricity), flow rate, energy efficiency, price, and warranty. Here is a list of the best Rinnai tankless water heaters you can find in the market today.


Best Rinnai Tankless Water Heater Reviews

  1. Rinnai RUC98iN Ultra Series Natural Gas
  2. Rinnai RL75IN
  3. Rinnai RL94eN Natural Gas Outdoor
  4. Rinnai RUR98iN Ultra Series Condensing Indoor Natural Gas Tankless
  5. Rinnai RU199iN


1. Rinnai RUC98iN Tankless Water Heater (Best for Large home)

Best Rinnai Tankless Water Heater

check price amazonThis tankless water heater has a capacity of 9.8 GPM (gallons per minute) and has a 0.96 energy factor, which means it is extremely efficient. This means that only 4% of the heat can be lost. It is Energy Star certified. On average, you will save 30% on your gas bills. The low flow rate trigger is 0.4 GPM. The emission of harmful gas is extremely low, making it environment friendly. This water heater can serve the needs of the entire family. It is very compact and weighs 61.7 pounds, so it will easily fit in your bathroom.



  • It has a capacity of 9.8 GPM
  • The energy factor is 0.96
  • It is compact and lightweight
  • The temperature is easily adjustable


The control panel has gas and water control and a digital display. If you want you can lock the temperature button, so others in the family won’t be able to adjust the temperature. This is a safety feature and is very helpful if you have children.


Installation of this water heater is very easy. It has isolation valves which are very helpful in preventing the build-up of hard water that can damage the heater. For venting, you can use PVC pipes or stainless steel concentric venting kit. The range of water pressure that the heater can work with is from 50psi to 150 psi. Therefore, it is ideal for installing in both old and new homes.


This water heater is suitable for residential and commercial indoor use. The residential heating capacity is up to 140 degrees Fahrenheit and that of the commercial heating capacity is up to 185 degrees Fahrenheit. The moment you open your hot water faucet, you will have an instant gush of hot water. This is because the water passes through the unit and doesn’t store in the tank. This reduces the chance of bacterial contamination.


You get a warranty of 12 years with this heater. So, within this period, you are fully covered for most of the defects. Though the warranty period is 12 years, the heater can last for up to 20 years. If you have more than four members in your family and if the use of the heater is frequent then the Rinnai RUC98iN is a good choice.

  • It has energy factor of 0.96 which is very high.
  • It includes PVC venting.
  • Easy installation.
  • Decent warranty period.
  • High price


2. Rinnai RL75IN (Best for small family)

Best Rinnai Tankless Water Heater reviews

check price amazonIf you live in a warm area and your family size is not that big then this unit is a good water heater. It will take up small space and looks very attractive. The unit has a capacity of 7.5 GPM and a flow rate of 0.4 GPM. It has low NOx emissions. The energy efficiency is 82% which indicates that not much heat is lost. So, you will be able to save your gas bill every month.


  • It has capacity of 7.5 GPM
  • The flow rate is 0.4 GPM
  • Energy efficiency is 82%
  • Leak detection and anti-frost functionality
  • Temperature control from 98 to 140 degrees Fahrenheit


Though the size of the heater is compact, you will never run on hot water. The moment you turn on your faucet you will instantly have hot water. Ou can control the temperature from 98 to 140 degrees Fahrenheit. It can provide a constant hot water supply to up to 4 fixtures simultaneously. For example, you can use a dishwasher, a laundry machine, and two showers at a time.


If there is any issue with the water line then this water heater has leak detection features that will close the valve to the water supply automatically. This will reduce further damage and prevent your bathroom from getting flooded. There is a built-in thermometer to detect the temperature. If it’s too cold, the anti-frost protection mode will be activated and it will run on low energy so that the water inside the tank doesn’t freeze and burst the water pipe.


Installing this water heater is very simple; everything is given in the manual. It comes with an isolation valve, which makes maintenance easy. The heater is appropriate for indoor use. You get 12 years warranty on the heat exchanger. This water heater is suitable for families of 5 to 6 members.

  • Lightweight and compact.
  • Energy efficient.
  • Low NOx emission.
  • Suitable for big families.
  • 12 years warranty.
  • Takes some time to heat the water.



3. Rinnai RL94eN Natural Gas Outdoor (Best for Commercial use)

Rinnai Tankless Water Heater reviews

check price amazonThis is an outdoor tankless water heater that can meet your everyday hot water needs. With a capacity of 9.4 GPM, it provides enough water for the entire family. Like most of the other Rinnai water heaters, the low flow rate trigger is 0.4 GPM. It is Energy Star qualified, so you can save a lot of energy; in fact, its thermal efficiency rating is 83%.


  • It has a capacity of 9.4 GPM
  • It has a low flow trigger of 0.4 GPM
  • The water can heat up to 140 degrees Fahrenheit
  • Isolation valves included
  • Wi-Fi capable


The water heater has a touchpad and digital display that lets you control the temperature. It is possible to heat the water up to 140 degrees Fahrenheit. Unlike some other models, this model works even in low pressure. You need to wait for some time for the water to be hot as the water is not heated in the pipe. However, if you can place the water closer to the water source then you can get instant hot water.


The isolation valves are included for easy maintenance. This water heater provides freeze protection, so if you live in an area where the temperature goes below the freezing point, this water heater will be appropriate. This heater is sufficient to meet the needs of a family of five members. It is possible to run multiple fixtures in up to three bathrooms. 


Unlike many other Rinnai tankless water heaters, this one is Wi-Fi capable. That means you can use your smartphone or computer to control the water heater. You can adjust the temperature easily. To ensure that the heater works efficiently all the time, it needs to be backflushed once every year. It has a sensor that indicates when you need to back flush it. You get 12 years of warranty with this product.

  • High capacity to serve large family.
  • Auto freeze protection.
  • Run on multiple fixtures simultaneously.
  • Wi-Fi capable.
  • Good warranty period.
  • Requires a minimum flow to operate.
  • It must be back flushed each year.
  • The water doesn’t get hot instantly.



4. Rinnai RUR98iN Ultra Series Condensing Indoor Natural Gas Tankless

check price amazonIf budget is not a constraint, then you should go for this model of Rinnai tankless water heater. It has the best thermal efficiency rating of 96%. So, even it will cost you more than the other models, you will be saving money over the long run in your monthly gas bills. With 9.8 GPM capacity, it is adequate to serve a large family. It has recirculation capacity. With both concentric and PVC venting options, installation becomes very easy. Isolation valves are also included for easy maintenance. As it is Wi-Fi capable, you can easily control its operation using your computer or smartphone. You can use Alexa too.


  • It has thermal efficiency rating of 96%
  • Built-in circulation pump
  • A by-pass pipe for internal “recirculation”
  • Isolation valves


With this heater, you can get endless water for your large family. It is possible to use multiple fixtures at once without compromising the temperature. The heat exchanger will start at 0.4 GPM. This is one of the best models of Rinnai tankless water heater if your family has a lot of demand for hot water. Even when the guests stay in your house, you won’t have any trouble supplying them with hot water. It is a condensing tankless water heater and that’s why it is so energy efficient. You can save at least 10% more money on your gas bill by installing this heater compared to the non-condensing water heaters.


Installing this tankless water heater is very easy. You can use either the concentric or dual PVC venting kit. If you like you can install it yourself as well using the manual, thus saving money on installation. The water heater is very convenient to use. The LED display has everything and you can understand all the controls at a glance. You can set it at any temperature you want.


You need to do flushing once at least a year to decline the heater. You will get an automatic alert if the heater needs maintenance or if it has any problem. If you do regular maintenance, the water heater will last for more than 15 years. So, over its lifespan, you will save a lot of money compared to that of the other tankless water heaters. With Rinnai RIR98iN you will get endless and instant hot water all the time.

  • High thermal efficiency.
  • PVC venting option.
  • Wi-Fi capability.
  • LED display.
  • Auto-maintenance alert.
  • Long lifespan.
  • Expensive.
  • Not appropriate for small homes.
  • Need to hire a professional for installation.



5. Rinnai RU199iN (Best Multipurpose)

check price amazonThis tankless water heater has earned the Energy Star label which means that it will save your energy bills significantly. With a 0.96 EF rating, it is 10% more efficient than the average tankless water heaters you will find in the market today. The water heater will last for more than 20 years, so imagine how much money you are going to save on your bills in the long run. It has 7 GPM to 11 GPM maximum hot water flow and so comes in different sizes. For a small family 7 GPM, medium family 9 GPM, and large family 11 GPM is appropriate. So, this tankless water heater is suitable for installing in any household.



  • It has Energy Star label
  • Water flow capacity is from 7 GPM to 11 GPM
  • Ultra-low NOX certified
  • Wi-Fi capable


It has a built-in recirculation pump. This pump circulates hot water from the water heater to a faucet that is located far away and this is a continuous process. So, within a few seconds, you will get hot water from your taps and showers. It is ultra-low NOX certified, so is very environmentally friendly and maintains good air quality inside the house. This unit has a built-in Wi-Fi module and can be controlled by Alexa as well. It has a water flow sensor, temperature controller, leak protection, frost protection, and even a scale detection system. The digital control panel is easy to operate. You get a 10-year warranty for the heat exchanger. The water heater is extremely reliable and cost-efficient.

  • Has high energy factor of 0.96.
  • Environment-friendly.
  • Emits low NOX.
  • Can be controlled by smartphone or Alexa.
  • It takes some time for the hot water to reach the faucets.


How Long Do Rinnai Tankless Water Heaters Last?

For water heaters this expensive trust me they will be around for years. Rinnai water heater has a 12 years warranty which means for the next 12 years you have nothing to worry about. These units can be expensive but they are worth every penny based on there durability.

Buying guide

Rinnai tankless water heater is popular because it is more compact than the other similar products in the market, yet it can hold a lot of water. You get long warranties with this water heater and so it is reliable. Here are some factors you should consider when buying Rinnai tankless water heater.


When you think of buying a tankless water heater you must first decide about the capacity of the heater. This will depend on your family size and usage rate. If you are living in a cold region then you will need hot water more frequently.

Energy efficiency

The Rinnai tankless water heaters also vary according to energy efficiency. If you want to save money on your energy bills you should choose a model that is at least 80% energy efficient.

Environment friendliness

Most of the Rinnai tankless water heaters are environment friendly. So, the quality of air inside the home won’t be compromised. You should choose a model with less NOX emission.

Wireless technology

The adoption of wireless technology and smart control in the different models of Rinnai tankless water heaters make them very comfortable to operate. The automatic features help to save energy and do regular maintenance.


Unlike the other brands, with Rinnai, you won’t have to worry about installation too much as the process is very simple. As these water heaters come with long warranty periods, you can consider them to be reliable. These water heaters will work efficiently without the need for much maintenance. If you already have the conventional water heater installed then you can switch to the tankless one conveniently. The conventional water heater is bulky and when you replace it with the Rinnai compact tankless water heater, you will see how much uncluttered space you get in your bathroom.


The various Rinnai tankless water heaters just discussed are the best in the market. They will fall within your budget and buying one of them will be one of the best decisions you will make for yourself and your family.

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