Noritz NR Tankless Water Heaters: Review and Buying Tips

noritz nr98Noritz NR98
(photo: amazon)

A review of the smallest and most affordable Noritz NR tankless water heaters, including indoor and outdoor models, and features that provide reliable, efficient, and cost-effective water heating.

Either you need a water heater for a house with up to three bathrooms or a small unit for point-of-use service that can heat water on-demand and always provide a sufficient amount of hot water; the NR series of water heaters is the group you should consider.

The Noritz NR series of tankless models are ideal for new homes and retrofits when replacing a gas or electric tank-type water heater. As the tankless models are wall-hanging, the floor space, which was previously used by the tank unit, now becomes available for other use. Plus, you have more flexibility during installation due to its small and lightweight size and long vents.

Except for saving space, fresh water is always available, and there is no more stand-by heat loss.

In addition, NR models can last at least 20 years.

Noritz NR water heaters: Models review

In a group of NR tankless water heaters, there are four sizes to choose from (listed below), designed for indoor and outdoor installations:

  • NR98
  • NR83
  • NR662
  • NR501

The NR group of tankless water heaters is the non-condensing group with an energy efficiency of around 83% for natural gas, making it one of the most affordable.

As opposed to condensing, the NR group of indoor models cannot use the PVC pipes for venting, but the pipes are made of stainless steel, as the temperature of the exhaust gases is higher. The outdoor models are ventless and do not require exhaust and air intake vents.

All the models utilize advanced electronics, which helps in providing an accurate and stable temperature, reliable operation, and diagnostics.

Noritz NR98

The Noritz NR98 model is the largest and most powerful unit in the NR series. It is designed with the maximum gas input of 199,900 BTU, and thanks to the modulating valve, the minimum power can go to as low as 12,000 BTU when low water flow is needed.

When the unit operates with its maximum capacity, it could produce a water flow rate of 9.8 GPM, making it ideal for homes with up to 4 baths in the warmer area and up to 2 baths in colder regions.

The maximum working water temperature is 140 F.

There are three models to choose from, all coming in the same size:

NR98 DVC – Direct concentric vent for indoor use

NR98 SV – Power vent for indoor use

NR98 OD - Ventless and designed for outdoor use

Noritz NR83

Noritz NR83 is the second largest model in this group. It can provide a water flow of up to 8.3 GPM, thanks to the powerful 180,000 BTU gas burner and higher efficiency. It can use both natural gas and LP, easily heating 2-3 bath homes in the warmer climates and up to 2-bath homes in colder regions.

The NR83 model is available only as an indoor model utilizing a direct and concentric venting system (DVC).

Noritz NR662

Noritz NR662 is the second smallest model available from Noritz, which comes with a maximum power of 140,000 BTU and a water flow rate of 6.6 GPM. This is what makes them suitable for smaller homes, condos, apartments, and smaller families, and used in point-of-use applications, or maximum 2 fixtures, but in the warmer regions.

It is available only as of the outdoor (OD) model.

Noritz NR501

Noritz NR501 is the smallest and lightest model from Noritz; it has dimensions of 20.5 x 13.8 x 6.7”, and it weighs 33 lbs. It can provide up to 120,000 BTU of power and a water flow rate of 5 GPM, so it is great for point-of-use services in small houses, apartments, cottages, townhouses, and places with up to 2 showers.

It is available only as the outdoor (OD) model but can use both natural gas and propane. It has a warranty of 12 years on the heat exchanger.

Features review

Heat exchanger

Noritz NR water heaters, as opposed to condensing models, utilize only one heat exchanger made of commercial-grade copper, which is thicker than the one found on standard models. This is what makes it more resistant to mechanical and thermal stress resulting in reliable and long-lasting operation.

The gas burner, which heats the water inside the heat exchanger, is the standard single flame type, fully modulating and adjusting the power level based on the needs.


Indoor models use mainly direct venting (DV), while some use standard power vents (SV). They should not be installed outside. Due to the higher temperature of the exhaust gases, these vents are made of stainless steel.

The outdoor models are ventless and are designed for outdoor installation only. Stronger models can be installed outside even in colder weather, while smaller models, NR662 and NR501, outside, but only in warmer climates. If the freeze protection kit is installed, it can also be installed in colder weather.

Quick connect

If more hot water is needed, two units can connect and provide twice the hot water capacity by using the Quick-connect cable.

Temperature control

NR662 and NR501 use the small, digital display to show the temperature, while the NR981 and NR83 use the remote thermostat attached to the front panel, so you can adjust and monitor the temperature you want (as long as it is within the specs). NR662 and NR501 can heat water from 115 to 140 F with only 6 settings, while other models have more options.


If replacing your old tank-type water heater with the Noritz NR model, you will notice one significant difference; how small these units are. For example, the largest model, NR981, has the size of only 23.6” X 13.8” X 10.2” and weighs 47 lbs, making it easy to install on the wall and almost anywhere inside the house. As said, NR models can be installed outdoor and indoors, where the vents can run horizontally or vertically.

Features highlights

  • Small, compact, and lightweight design allows easy handling and wall installation.
  • Fast and reliable electronic ignition.
  • Over 82% energy efficiency.
  • Commercial-grade heat exchanger for longer life.
  • Modulating gas valve allows power adjustment, saving fuel and water.
  • Quick Connect cable available to connect two units into one system and provide more hot water.
  • Advanced electronics for easy monitoring and diagnostics.
  • Long warranty of 12 years on the heat exchanger in residential applications.

Safety elements

  • Thermal fuse provides automatic protection from overheating
  • Flame rod
  • Lightning prevention device
  • Fan rotation detector
  • Freeze protection

Useful accessories

  • Scale detection function
  • Temperature lockout
  • High elevation adjustment
  • Service reminder function


Models / Specs NR98 NR83 NR662 NR501
Gas input (BTU) 16,000-199,900 18,000-180,000 15,000-140,000 15,000-120,000
Water flow (GPM) (@30 F temp.rise) 9.8 8.3 6.6 5.0
Energy factor 0.88 0.85 0.81 0.81
Temp. settings (F) 100-140 100-140 100-150 115-140
Energy consumption (Watts) 65-83 82-90 38-39 35-38
Weight (lbs) 54 49 36 33
# of baths 3-3.5 1-3 1.5-2 1


Yes, tankless water heaters from the Noritz NR series cost slightly more than the conventional tank-type, but due to efficient and on-demand heating, continuous and endless hot water supply, innovative technology, and advanced electronics, the NR group of heaters are simply a better solution. They offer quality features, durable construction, and elements, covered by the long warranties of 12 years.

Either you are planning to buy a large Noritz NR981, NR83, NR662, or the smallest NR501, you are getting high performing unit with a minimum energy efficiency of 82%, resulting in energy, water, and money savings, including low gas emission, installation versatility, and better comfort.

Again, choose Noritz NR981 or NR83 if you have a 2-3 bath home, NR662 for a home with up to 2 baths, and NR501 for a one bath home or apartments. For outdoor use, use only NR981 and NR83 models in colder climates without using the additional accessories.

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