Compare Tankless Water Heater

Bosch, AO Smith, Rheem, Rinnai vs. Noritz Comparison

Compare tankless water heater article is about finding the best water heater for your hot water needs, by comparing the top on demand heaters manufacturers offered in North America. This comparison will cover gas tankless appliances for residential use, for an average/large homes with 2 plus bathrooms and family size of four and more.

We review top manufacturers of tankless water heaters, compare the benefits and the main features and extract what is specific for that particular brand. You will find our pick of several best brands, including Rheem, Bosch, Rinnai and Noritz.

To compare tankless water heater models in details you have to go through every single model, and that is why we encourage you to visit our brand review sites, with a link positioned on the navigation bar. These detail reviews will show you all the popular models from a specific on demand water heater manufacturer.

When we were reviewing and comparing all these top gas on demand appliances we have found many common features and benefits:

  • Life span of tankless water heaters is around 20 years.

  • Majority of the parts are replaceable and recyclable.

  • All the presented tankless water heaters are high efficient with EF 0.82 or higher, and EnergyStar qualified.

  • They use the latest innovative engineering with green technology that is increasing performance while reducing greenhouse CO2 and NOx gases emission.

  • These on demand water heaters use direct electronic ignition to ignite the gas burner.

  • Great protection with safety features like flame failure, overheat, power failure...

  • Materials they are made of are superior quality.

  • They are designed to work on both natural and propane gas.

  • Maximum input power they got is around 199,900 BTU.


Bosch Aquastar 2700ES

Bosch AquaStar 2700ES


Aquastar 2700ES is Bosch's top and the most powerful residential tankless water heater, powered by either natural or propane gas.

Compare tankless water heaters by using the top features from Bosch Aquastar 2700ES model:

  • Solid copper heat exchanger for efficient heat exchange.

  • Modulating gas valve for improved combustion.

  • Modulating water valve for better comfort and hot water control.

  • High efficiency Ceramat Burner with low NOx emission.

  • Two fans for better performance; primary fan is the mixer and secondary air fan. Fan speed adjustment.

  • Front panel has an LCD display with key pad interface control for temperature and failure code display.

  • Wireless remote to control the temperature of the hot water.

  • Option to install outside with an outdoor kit.

  • Pressure relief valve supplied.

  • High altitude options up to 4500 and 8000 ft.

  • 12-year warranty on heat exchanger and 2 years on other replacement parts for residential installations.

.. for more information use Bosch tankless water heaters review.


emergency plumber

Rheem RTGL74

Rheem Outdoor Liquid Propane & Natural Gas Tankless Water Heater


Rheem RTGL74 models are top of the line units available from this North American manufacturer of tankless water heaters.

Features to consider for Rheem RTGL74 tankless water heater comparison:

  • Environmentally friendly gas burner with low NOx emission.

  • Wireless remote to control the temperature of the hot water.

  • Intelligent electronic system and self diagnostic program.

  • EZ Link to connect two tankless units to operate as one, for high demand application.

  • Guardian SBT sensing burner technology.

  • Guardian OFW overheat film wrap.

  • Two high altitude options up to 6560 and 9840.

  • Option to link up to 20 unit manifold installation.

  • Three tankless models available: Indoor, Outdoor and Direct vent.

  • 12-year warranty on heat exchanger and 5 years on other replacement parts for residential installations.

  • Rheem RTGL74 price is around $950.

.. for more information use Rheem tankless water heaters review.


Rinnai R94LS

rinnai tankless water heater r94lsi

Features to consider for Rinnai R94LS tankless water heater comparison:

  • Commercial grade heat exchanger

  • Integrated digital controller available with the error code indicator.

  • Integrated condensate collector on the indoor model.

  • EZConnect to connect two tankless units to operate as one, for high demand application.

  • High altitude options up to 10200 ft.

  • Option to link up to 5 tankless into one water heating system.

  • Indoor and outdoor venting installation.

  • 12-year warranty on heat exchanger and 5 years on other replacement parts for residential installations.

  • Rinnai R94LSi price is around $1100.

.. for more information use Rinnai tankless water heaters review.

Noritz N-0842MC

Noritz N-0842


Noritz models N-0842MC is the condensing tankless water heater with the new dual flame burner technology. When you compare it with other tankless brands you will see that nobody else offers such a technology. This is the latest engineering with a specially designed second row of burners that allows the increased level of gas burning efficiency.

Japanese engineering is known as the best in the world, so even when you compare two Japanese water heaters, Rinnai vs. Noritz for example, you will see a difference in quality and performance.

Features to consider for Noritz N-0842MC tankless water heater comparison:

  • Dual heat heat exchanger - fusion of stainless steel and commercial grade copper heat exchanger with 25% thicker piping.

  • Over 93% energy efficiency.

  • Great reduction of CO2.

  • Due to lower exhaust temperatures less costly PVC venting is used, instead of expensive stainless steel.

  • Turbo flow feature allows higher hot water flow.

  • Amazing 8.4 gallons per hour for 45 degree rise, others are in a range of 7 gpm.

  • It uses Quick-Connect to connect two identical units to double the heating output.

  • It also uses a multi system to connect up to 24 units.

  • Recirculation compatible.

  • Self diagnostic onboard computer system.

  • 12-year warranty on the heat exchanger and 5 years on other replacement parts for residential installations.

  • NORITZ 8.4 GPM price is around $1700.

...for more information use Noritz tankless water heaters review.


Related Articles

(All pictures are courtesy of Amazon)