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 the 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 tank-type heaters.

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

NoteProfessional installation and repair are recommended. Find local plumbers and get FREE Quotes!

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, and with the help of the modulating gas valve and smart electronics, can be 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 using the Quick-Connect cord, resulting in more power and hot water flow.

Noritz NR83

Noritz NR83 is available only as of 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 a flow rate of 8.3 GPM, the NR83 is recommended for homes with up to 3 baths.

Noritz NR662

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

With the maximum power of 140,000 BTU and a water flow rate of 6.6 GPM, the 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 the Noritz NR group. It comes with the size of only 20.5" x 13.8" x 6.7" and a weight of only 33 pounds. With the lower water flow rate of 5 GPM, it 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, a 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 capable of generating maximum power of 199,900 BTU (top models). With the help of the modulating gas valve, it can provide stable water temperature with the low NOx gas emission.

Efficient heating

The Noritz NR series consists of mid-efficient water heaters equipped with one commercial-grade copper heat exchanger, which can heat water with an 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 a 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 ventless, power vent, direct vent, with the twin-pipe or concentric type configuration.

Safety features

All models from the Noritz NR series are equipped with the safety features for 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 used for residential water heating come with a 12-year limited warranty on heat exchangers, 5 years on other components, and one year on labor. When used in commercial applications, the warranty for the unit is reduced.

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


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