Rinnai RUC98iN Ultra Series Tankless Water Heater Review


There are certain utility-related appliances that are expensive to replace, but it happens to all of us. If you find yourself in need of replacing your hot water heater and you want to choose a more efficient solution for hot water, it is recommended that you consider choosing a tankless water heater. With a tankless water heater, your water is heated on demand, whenever you turn on the hot water tap. This is opposed to the way that a traditional water heater operates: keeping a huge tank of water hot and ready to use at all times. Think of all that waste!

Even larger homes or bigger families can benefit from a tankless water-heating system. There are systems that are perfectly suited to those with higher-than-normal hot water needs that still provide significant savings you will see by way of reduced utility costs.

Things to consider when buying a gas-powered tankless water heater

When choosing a hot water heater, you want to first determine what kind of heater you are looking for. Whatever the source of your home’s power will be the type of heater that you should look for. However, gas powered is sometimes not all inclusive; sometimes it means natural gas, sometimes it means propane, and you will need to ensure that you are looking at the right kind of gas heater.

A huge caution and recommendation: Do not install a gas-powered tankless water heater on your own if you don’t have significant experience with this type of work. Gas-powered tankless hot water heaters require ventilation and perhaps even the installation of gas lines or plumbing work in order to be properly installed. Most people don’t have this kind of experience, which can make it dangerous to try if you don’t really know what you are doing. With a professional, you get the peace of mind that your system is properly installed and safe to use.

Rinnai RUC98iN Ultra Series Natural Gas Tankless Water Heater

Rinnai is a trusted maker of a range of utility-related products and accessories, such as water heaters, components, and accessories for repair and regular maintenance of said appliances. They make a line of tankless hot water heaters that utilize cutting-edge technology and are known for their durable design and efficiency.

This is a higher-end system that is well suited for people with greater-than-average hot water requirements, or for a large family. This is a whole-house system and it a good-value system for a high-capacity full-house system.

This unit is constructed from tough and durable materials to stand the test of time, and you also have your choice of PVC or concentric venting. It is a small unit that packs a big punch, allowing you to have all the hot water you want, without wasting a ton of space in the process.

It comes with several additional features and benefits including:

  • An incredibly energy-efficient unit that has up to a .96 Energy Factor.
  • It has a max of 199,000 BTU and is Energy Star compliant.
  • The unit comes with a 12-year limited warranty on the heat exchanger and a 5-year warranty on parts. It also comes with a 1-year warranty on labor. This gives you peace of mind knowing that you are protected in the event that something goes wrong with your unit.

The unit boasts low NOx emissions, making it more environment friendly than comparable units, though if you live in a state with strict environmental regulation it helps to double check to ensure this unit is in compliance with said regulations.


Tankless hot water heaters are a great way to reduce your energy consumption and, as a result, your overall environmental impact. These systems give you access to on-demand hot water, without all the waste and costs associated with traditional hot water heaters. Rather than keeping tens of gallons of water continuously heated in the event you need it, a tankless system waits to heat the water until the hot water tap is turned on.

The Rinnai unit we reviewed here is a great option for those who have hefty hot water needs or those with larger houses and/or families. This is a great value for a gas-powered, whole-home system that will provide you on-demand hot water, requiring a fraction of the energy. With a tankless system, you do not have to sacrifice water temperature to reduce your waste and improve efficiency.

Rinnai RUC98iN Ultra Series

Rinnai RUC98iN Ultra Series


8.9 /10


9.5 /10


  • excellent capacity and energy efficiency
  • runs on both propane and natural gas
  • 12 years warranty on heat exchanger


  • can be difficult to install
  • bulky compared to many other models

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