Rinnai RUC98iN Gas Tankless Water Heater Review

The Rinnai RUC98iN Ultra Series is one of the most energy efficient tankless water heaters on the market. Is it worth the investment? Find out in our review.


The Rinnai RUC98iN Ultra Series is one of the most energy efficient tankless water heaters on the market. Is it worth the investment? Find out in our review. If you have been experiencing some problems with your water heater, it probably needs a replacement and it…

Rinnai RUC98iN Ultra Series Gas Tankless Water Heater

Ease of Use

Amazing Efficiency

This is one of the most energy efficient tankless water heaters around. It has an Energy Factor of .96 and is ENERGY STAR qualified. It is the only manufacturer to offer concentric and PVC venting options, which gives you the flexibility to install it in just the way you want. Advanced technology produces lower CO2 emissions, while NOx emissions are really low too. The catch is that you pay a bit more for the Rinnai name. Still, you can be assured of its quality.

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If you have been experiencing some problems with your water heater, it probably needs a replacement and it is about time that you look for a better performing one. Almost everyone is taking advantage of what technology can offer by transferring to a tankless water heater for their homes. If you are not very familiar with these products, then you can check out our guide to tankless systems. In this post we compare the best models and discuss the key features you should be looking for. 

To understand this specific product better, it is also important to know how tankless water heaters actually work. Most people are used to having a storage water tank heater and know that this type of heater keeps a huge amount of water inside a large tank, keeping it warm for whenever you or anyone in your family are ready to use hot water.

A tankless water heater, on the other hand, will only give water on demand. This means that it will only heat water up when you turn the hot water tap on. The water is heated through a process using propane, natural gas, or electricity. No water needs to be stored inside a tank as everything is done on demand. With this type of heater, the water can turn from cold to warm in just a few seconds.

The RUC98iN gas tankless water heater was manufactured by Rinnai, who are one of the industry’s benchmark companies. They have been in the business for 45 years, and are known to deliver high quality and innovative water heating and home heating appliances for both residential and commercial use.

This Rinnai tankless water heater reviews really well on sites like Amazon where it has an average rating of 4.6 stars.


Product Features

  • The Rinnai RUC98iN is an indoor gas tankless water heater which uses propane or natural gas and has either concentric or twin pipe PVC venting options.
  • It complies with nitrogen oxide emission standards.
  • It stands 26 inches tall and weighs 61.7 pounds, which obviously shows that even if it is compact and has a sleek design, it is not lightweight at all. But, although quite heavy, the space saving and sleek design allow it to be installed almost anywhere in the house.
  • The exterior is gunmetal gray where the controls can also be found, specifically on the lower portion of the front panel. The controls include a power button, gas control and water temperature buttons, as well as a digital display.
  • It allows control of the temperature of hot water coming out and you can even lock the temperature button to prevent unauthorized access. That way, you will be ensured that the water temperature will always be constant and will not be too hot for children or the elderly.
  • It has bigger inlets and outlets than most gas tankless water heaters and is also bigger and heavier but more powerful too. It has an energy factor of 0.95 which is higher than the average for water heaters powered by gas.
  • It can supply sufficient hot water to multiple showers and faucets in a house with several bathrooms and there will be no interruption to the flow of hot water. This can be attributed to the fact that this heater has a minimum to maximum gas burn rate varying from 15,200 to 199,000 BTU which is considered to be a very wide range. Its hot water flow rate range is also wide at 0.26 to 9.8 gallons per minute, while the minimum activation flow rate is only 0.4 gallons per minute.
  • It is capable of heating water from any temperature to 95 to 140 degrees Fahrenheit and in fact, the commercial model has the capacity to provide water as hot as 185 degrees Fahrenheit.

Pros and Cons

Here are some of the benefits that the Rinnai RUC98iN tankless water heater offers:

  • It does not need a lot of space so you will have more space at home, which can be used for other purposes.
  • It helps save the environment because of its energy efficiency ratings. It saves energy by heating water only when needed.
  • It also helps in the reduction of electricity consumption and saves a considerable amount of water.
  • It is quiet and does not make any distracting sound.
  • Since it is tankless and does not store water, there are lesser chances of getting any kind of unwanted residue from the faucets or shower heads. This makes this heater a cleaner alternative. The water is not stored in a metal tank that can build up scale and rust, which can eventually pollute the water that you use for bathing, brushing your teeth, cleaning, and even cooking.
  • Hot water supply is unlimited and there is no waiting time, unlike a conventional water heater. The latter needs to heat more water once the supply has been used up and that may take a while.

However, there are also things which some people did not like and could have been better on the RUC98iN:

  • The price is a bit higher than most gas tankless water heaters available in the market.
  • It is bulkier than most tankless water heaters. Though when compared to a traditional tank based system it is very small.
  • It is quite difficult to install and even requires maintenance to be conducted by a repair personnel certified by Rinnai. This is essential so as not to avoid warranty. Take note that the installation process may require a significant amount of money since it has to be conducted by a certified professional.

The Bottom Line

With an unlimited supply of hot water, savings in the energy and water consumption, great space-saving design, and environmental benefits, it is hard to say no to this product. As indicated, there are many features that would make you want to move from a conventional water heater to a tankless one. Just make sure that you consider the potential issues that were mentioned earlier. If you think that those will not be of major concern, then this might be the perfect choice for you and your family.

Check back soon for more Rinnai tankless water heater reviews.

Hard water is a particular pest to water heaters as it builds up scale on the fixtures like the heating element. This affects the lifespan of the appliance. Check out our guide to water softeners to find out more about these products that prevent scale build up.

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