Rinnai Condensing Water Heaters
Review and Buying Tips
(updated 2019)

A review of Rinnai condensing water heaters from RUR, RU, RUCS, and RUS series. Check out the advantages and benefits when buying one of the top of the line Rinnai water heaters with tankless and condensing technology.

Rinnai condensing tankless water heaters are coming from the "Ultra" series, a series of the most advanced and efficient models. Condensing models have the same modern and stylish look as other tankless and non-condensing models, similar size of 18.5" x 26" x 10", lightweight design around 70 lbs, and flexible installation options either outside or inside a home.

But, models such as those from the RUR series go a step further, offering many innovative features for the unmatched user experience. 

Rinnai condensing difference

Rinnai condensing water heaters kept the same advantages and benefits of the tankless technology; heating water on demand, delivering hot water in endless and continuous supply at a preset temperature, simultaneous hot water delivery to the multiple appliances without temperature fluctuation and unpleasant "cold-water sandwiches."

So what makes them truly different is the ultra-high energy efficiency reaching high 0.96 energy factor (EF), ultra-low NOx gas emission, recirculation, advanced electronics, and smart technology. Good examples are RUR199 and RUR160 models.

The ultra-efficiency is possible because of the Rinnai condensing technology that utilizes two heat exchangers; the copper heat exchanger gets the heat energy from the gas burner, while the other, stainless steel one gets the heat from the exhaust flue gases.

The secondary heat exchanger is actually used to pre-heat the incoming cold groundwater. Also, since it is exposed to the acidic nature of the condensate, it is made of durable stainless steel.

The result of this condensing technology is higher efficiency of up to 0.95-0.96, as opposed to the standard tankless units, which can provide efficiency of up to 0.82. Also, the units produce flue gases with the lower temperatures so they can use different vent types, such as; PVC and CPVC, replacing the expensive stainless steel.

The flexible venting options, such as direct and non-direct, make the installation faster, cost lower, and with the zero clearance from combustible - safer.

These models can also be used for home heating, but only combined with domestic water heating, even manufactured housing.

Models review

There are several groups of Rinnai condensing water heaters, designed for heating potable water from mid- to large-sized homes, or homes with up to five to six bathrooms/fixtures. Due to the high performance and superior energy factor, all the models are Energy Star compliant and eco-friendly, offering significant energy savings and reduced gas emission.

There are three groups of Rinnai tankless water heaters with condensing technology:

  • Rinnai RUR models
  • Rinnai RU models
  • Rinnai RUCS (RUS) models

Rinnai RUR water heaters

Rinnai RUR condensing tankless water heaterRinnai RUR

Rinnai RUR models are known as the Super High-Efficiency Plus water heaters that are designed to provide an ultra-high energy factor of up to 0.95-0.96 and are among the most efficient tankless and condensing units from this manufacturer.

What makes them unique, and recommended by the experts, is the ThermCirc360 recirculation system, which, no matter of the plumbing configuration, provides hot water in less time and reduced energy waste, than the units without this system. Users will enjoy hot water delivery in no time.

The maximum capacity is 11 GPM so they can be used in large and demanding homes, delivering hot water to up to 6 showers simultaneously. The powerful gas burner with the maximum gas input of 199,000 BTU is capable of heating water fast and efficiently, with the ultra-low NOx gas emission and with the temperatures ranging from 98 F to 140 F.

Offering the cutting edge technology, Rinnai RUR tankless water heaters can provide amazing performance combined with the Wi-Fi remote monitoring and control, including convenience that the Amazon Alexa voice control system brings.

Available models:

  • Rinnai RUR199 – indoor and outdoor models using natural gas and propane (3-6 fixtures)
  • Rinnai RUR160 - indoor and outdoor models using natural gas and propane (2-5 fixtures)

Rinnai RU water heaters

Rinnai RU outdoor condensing water heaterRinnai RU

Rinnai RU condensing water heaters are available in four sizes that are installed indoors or outdoors, and powered by natural gas or propane:

  • Rinnai RU199 – indoor and outdoor models using natural gas and propane (3-6 fixtures)
  • Rinnai RU180 - indoor and outdoor models using natural gas and propane (3-5 fixtures)
  • Rinnai RU160 - indoor and outdoor models using natural gas and propane (2-5 fixtures)
  • Rinnai RU130 - indoor and outdoor models using natural gas and propane (2-4 fixtures)

Rinnai tankless water heaters from the RU series are designed to operate with the maximum power ranging from 130,000 to 199,000 BTU and provide hot water flow from 7 to 11 GPM, which is sufficient for medium and large homes with up to 6 fixtures. In commercial applications, they can reach high temperatures of 185 F, with a maximum efficiency of 0.96, and ultra-low NOx gas emission.

All the models are Circ-Logic capable, so if there is a need, they can be easily converted to use the recirculation for faster hot water delivery.

While the Control-R Wi-Fi module is included in the RUR series, RU models are capable of using it, but the module is optional - sold as an accessory. As the RUR models, RU also allows quick access service, where the pressure relief valve can rotate and accommodate the installation of the isolation valves.

Rinnai RUCS (RUS) water heaters

Rinnai RUSRinnai RUS

Rinnai RUCS and RUS models are the "smallest" tankless and condensing water heaters from the Rinnai manufacturer (considering the power and water flow delivery), and are available as:

  • RUCS65iN - indoor models using natural gas and propane (ideal for homes with 2-3 fixtures)
  • RUCS75iN - indoor models using natural gas and propane (ideal for homes with 2-4 fixtures)
  • RUS65eN - outdoor models using natural gas and propane (ideal for homes with 2-3 fixtures)
  • RUS75eN - outdoor models using natural gas and propane (ideal for homes with 2-4 fixtures)

All the RUS and RUCS models have the ability to adjust the power using the modulation, so the maximum power goes from 130,000 to 160,000 BTU while the minimum gas input they can work at is common for all - 10,300 BTU.

The energy factor is still high - 0.93, while the maximum water flow is in the range from 6.5 to 7.5 GPM, making them ideal for residential homes with up to 4 bathrooms. Only the RUCS75 and RUS75 are Energy Star compliant, while smaller models are not.

As opposed to the above models equipped with the temperature controllers, RUCS and RUS models include only a small status monitor at the front of the unit, while the temperature controller is optional.

The status monitor is designed to display the operating status and error codes. While the RUCS models are Wi-Fi and recirculation capable, RUS models can only take advantage of the Wi-Fi application.

Like other Rinnai tankless models, condensing water heaters are built with green technology in mind so that they can produce much less greenhouse gases, such as NOx and CO2.

Durable and long warranties

Rinnai condensing water heaters are durable and reliable; they can run for over 20 years with no problems. Even if something happens to its elements, they are replaceable, no need to get rid of the whole unit.

Rinnai RUR and RU models are backed by the 15-year limited warranty on the heat exchanger or 12 years on RUCS/RUS models, 5-year on other parts, and one on labor when used in residential applications.

Safety features

Safety features from below can be found on all Rinnai condensing water heaters.

  • If there is an excessive temperature increase inside the water heater, an Overheat feature will turn the unit OFF.
  • If the burner flame goes out for any reason, Flame Failure will turn the unit OFF.
  • Power Failure will cut the gas OFF if the unit loses the electrical power.
  • Overcurrent protection.
  • Fusible link will break and shut the unit down if the overheat feature does not react when the temperature rises above the maximum allowable.
  • Automatic freeze protection.
  • Rinnai condensing water heaters are already equipped with a condensate trap and condensate drain line.

Why should you buy one of the Rinnai condensing water heaters?

According to Builder Magazine, home builders have recognized Rinnai tankless water heaters like the "Best" in the industry.

Rinnai condensing technology brings the optimum heating and ultra-high performance as it's models utilize heat from the flue gases to pre-heat the incoming groundwater. The result is an incredible Energy Factor of up to 0.96, so homeowners can save not only on energy but water and time. The reliability is increased so as the durability, while the maintenance is reduced.

According to the US Department of Energy, high-efficient condensing tankless water heaters, such as those from Rinnai have the average annual operating costs of $171, non-condensing have $200 and standard 50-gal tank, around $273. This fact, great specs, and many advanced features are making Rinnai condensing water heaters a good buy.

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