Noritz NR
Tankless Water Heaters 
Review and Buying Tips

Check out the latest models and top features of the Noritz NR series of tankless water heaters for residential on-demand water heating.

Noritz NR water heaters from proTOUGH and valueSolutions series are designed as mid-efficient tankless units whose thermal efficiency is lower than the efficiency found on condensing NRCP models, but still higher than the efficiency seen on most of the tank-type heaters.

The NR series of water heaters still generates hot water on demand, in endless and continuous supply and its most powerful model NR981, with the flow rate of 9.8 GPM, can provide sufficient amount of hot water to homes with up to four baths.

Due to its small size and weight of up to 58 pounds, and thanks to the sealed combustion and many safety elements, NR series of tankless water heaters are easy and safe to install on the wall of the home, garage or office, and used for providing hot water in the whole house or point of use applications.

Since these units are non-condensing and the temperature of the exhaust gases is high, Noritz NR models cannot use the vent pipes such as the PVC or CPVC, but stainless steel, which is resistant to the corrosive nature of the flue gases.


Models review

Noritz NR981 tankless water heaterNoritz NR981

Noritz NR981

Noritz NR981 water heaters (available on are designed as the indoor; concentric direct-vent (DVC) and power or standard vent (SV) models, while the NRC-OD type is built as the outdoor model.

All the models are designed with the maximum gas input of 199,900 BTU, that can be, with the help of the modulating gas valve and smart electronics, reduced to 16,000 BTU, making it great for single fixtures and homes with up to 4 baths.

Two NR981 models can be linked together by using the Quick-Connect cord, resulting in more hot water delivery.

Noritz NR83

Noritz NR83 is available only as the indoor DVC model that uses the concentric direct venting system for removing the products of gas combustion. This is the second largest unit in the non-condensing group that has a power of 180,000 BTU and with the Turndown Ratio of 1:10, the power can be reduced to 18,000 BTU, and used for smaller jobs, such as shaving, face washing, and dishwashing.

With the flow rate of 8.3 GPM, NR83 is recommended for homes with up to 3 baths.

Noritz NR662

NR662 and below model NR501 are coming from the affordable group of tankless water heaters valueSolutions that are designed as power vented outdoor models, recommended for warmer regions and smaller applications.

With the maximum power of 140,000 BTU and water flow rate of 6.6 GPM, NR662 is great for homes with up to 2 baths but only for outdoor installations.

Noritz NR501

The NR501 water heater is the smallest unit in Noritz NR group that comes with the size of only 20.5" x 13.8" x 6.7" and weight of only 33 pounds, and with the lower flow rate of 5 GPM is an excellent choice for smaller homes, apartments and offices, or mainly for point-of-use service, supplying only one fixture with hot water. Since this is an outdoor unit, no venting is required. Also, if used in colder regions, freeze protection kit is needed.

Similar models: Rinnai V65 and Takagi T-KJr2


Powerful burner

NR models come with one single but efficient gas burner that is capable of generating the maximum power of 199,900 BTU (top models), and with the help of the modulating gas valve can provide stable water temperature with the low NOx gas emission.

Efficient heating

Noritz NR series are mid-efficient water heaters that are equipped with one commercial-grade copper heat exchanger which can heat water with the energy factor from 0.82 to 0.88, depending on the model and fuel type.

Temperature control and troubleshooting

Outdoor models NR662 and NR501 are equipped with the small LCD display window while the indoor NR981-DVC and NR83 have the remote controller built-in, showing the current status, temperature and error codes when the failure occurs. It is recommended to have the remote controller installed where applicable, for easy temperature adjustments and control.


The venting system is quite flexible as some models can be installed as the ventless, power vent, direct vent, with the twin pipe or concentric type configuration.

Safety features

    All models from Noritz NR series are equipped with the safety features for the unit protection:
  • Flame rod
  • Automatic overheat protection device
  • Freeze protection to - 30 F for an indoor and -4 F for outdoor models
  • Lighting protection device
  • Fan rotation detector
  • Temperature lock-out system to protect from high water temperatures
  • Resin coated PC board


Models/Specs Noritz NR981 Noritz NR83 Noritz NR662 Noritz NR501
Power (BTU) 16,000-199,900 18,000-180,000 15,000-140,000 18,000-120,000
Water flow (GPM) 0.5-9.8 0.5-8.3 0.5-6.6 0.5-5.0
max # of baths 4 3 2 1
Water/gas connections (inch) 3/4 3/4 3/4 3/4
Temperature (F) 100-140 100-140 100-140 115-140
Energy factor 0.81 0.81 0.81 0.81
Warranty 12 12 12 12


Noritz NR tankless water heaters that are used for residential water heating come with the 12-year limited warranty on heat exchangers, 5 years on other components and one year on the labor. When used in commercial applications, the warranty for the unit is reduced.

The NR series is the economy-value group of water heaters which are not equipped with the state-of-the-art features as condensing, but still with many great features for reliable and efficient heating in both small and large homes.


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