Best Tankless Water Heaters
Review and Buying Tips

Rinnai, Noritz, Paloma, Bosch or Takagi - which one is the best tankless water heater? Check out this selection and review of the top on-demand and non-condensing models in North America. 

This review covers the best tankless hot water heaters (non-condensing) from several manufacturers present in North America. All of the heaters are gas-powered using either natural or propane gas, are Energy Star compliant, have the most advanced features and quality materials, and are designed to provide the highest water flow, for high-demanding homes.

If looking for the best condensing gas heaters and the review of its features, check out this article.

Best tankless for residential use

How to select the best tankless

Tankless water heater

The best tankless water heaters are made of the quality and durable materials so they can last longer and provide reliable water heating for many years.

One of the main elements is the heat exchanger, which, due to the high thermal stress, has to be made of the commercial-grade copper or stainless steel, so it doesn't rust, can last longer and perform as expected.

The best models are versatile, have the flexible venting system, and can be installed anywhere inside your home.

The smart technology is a must today, so the model equipped with the diagnostic system is recommended as it provides easy troubleshooting, monitoring, and control of all important parameters.

The top models are listed below. Select a brand which comes with the decent service network, the models come with an extended warranty and have the spare parts, available anytime.

The best of Rinnai

The best tankless water heater from Rinnai, a Japanese manufacturer, is coming from the RL94 series. Rinnai RL94i is an indoor model that comes with the maximum power of 199,000 BTU and can produce high water flow of up to 9.4 gallons per minute, which makes it ideal for larger homes and up to five applications, even if working simultaneously.

It's high-efficient, and environment-friendly burner helps this Rinnai unit to deliver up to 40% in savings while emitting less NOx gases.

When working with the reduced power of 9,900 BTU, Rinnai will operate with the lower water flow (0.4 gpm), which is enough for applications where the smaller amount of hot water is needed.

The compact and lightweight design of 50 pounds allows easy wall mounting, which saves precious floor space, while its concentric venting system brings lots of flexibility in the installation, so the flue gases and air intake system are safe and reliable.

Temperature monitoring and settings change are very convenient as the controller is a standard feature, and is built-in while providing easy troubleshooting through the diagnostic code system.

The best of Noritz

The best tankless water heater, non-condensing, from Noritz is the model NR98-SV. Noritz NR98-SV is a gas model that is designed for indoor use and with the right kit, can be easily transformed for outdoor use.

With the maximum continuous water flow of 9.8 gallons per minute, NR98-SV is perfect for homes with up to four fixtures working at the same time. The commercial-grade heat exchanger, where cold water is heated, is thicker and more durable than those installed in Rinnai, Paloma or Takagi tankless models.

On the other side, a minimum flow of 0.5 GPM is still good enough for heaters activation, and when the smaller amount of hot water is needed. A fully modulating gas blower automatically adjusts its power to meet the set temperature and based on the water flow. Temperature fluctuations, which are common in most heaters, is reduced thanks to the dual flame burner. For those homes that need even more hot water, the Quick Connect cable allows connection of the two identical units into one system.

The best of Paloma

Paloma tankless

The best tankless water heater from Paloma, gas-powered and non-condensing, is model PH2-28RDVSN, coming from 9.5 or PH2-28 series, a high-volume series that can provide a maximum of 9.5 gallons per minute and enough hot water for two-three bath-homes.

 An environment-friendly gas burner is capable of heating the water with the thermal efficiency of 84%, where 11,000 BTU can provide enough energy for its minimum water flow of 0.4 GPM, while the power of 199,900 BTU efficiently heats 9.5 gallons of hot water per minute. For double performance, DUOnex cable is used to connects two identical units into one system.

Paloma's exclusive feature - an ICAD or Incomplete Combustion Avoidance Device is used to optimize gas combustion and shut the unit off in a case of the increased level of carbon monoxide. Another cool feature - an Overheat Limiter Wrap is the plastic film that is wrapped around the heat exchanger so in a case of the overheating it shuts down the unit.

As with the previous two models, an extensive diagnostic and error display is used on the remote control for easy troubleshooting and temperature control.

The best of Takagi

T-K4 model is the best tankless water heater from Takagi manufacturer, designed for residential water heating, mainly. Built as the most powerful and versatile heater, T-K4 works as the outdoor model with an option to convert the heater into the direct vent model and for indoor use.

The power goes from 11,000 BTU to high 190,000 BTU, and with the modulating gas burner, it is heating and delivering water from low 0.5 GPM to high 8 GPM. For high demanding applications, it uses the cable link to connect two units into one system.

The best of Bosch

Bosch Therm C 940 ES is the high capacity and high-efficient tankless water heater, which is designed to provide 9.4 gallons per minute of hot water for high demanding application. If more hot water is needed, an intelligent cascading will get up to 24 units connected into one system, operated by a controller.

Its direct-vent sealed combustion and dual fan technology allow an indoor installation almost anywhere within your home. With the correct kit, the C 940 ES model can also be converted for the outdoor installation.

Modulating premix burner and constant gas/air ration, combined with the modulating water valve, improves the gas combustion and temperature stability.

It is used not only for residential water heating but solar thermal and recirculation applications. A great 15-year warranty makes this Bosch tankless water heater a good buy.


So which one, from the above five brands is the best tankless water heater?

The best gas water heaters are coming from the reputable manufacturer, have lots of power (in BTU) and water flow rate (GPM) so you can get a lot of hot water, no matter the weather conditions and are you running two applications simultaneously. The best models are “green” with the ultra-low NOx gas emission and high efficient and protected by several safety features. 

Those models come with the advanced technology for the precise control and better diagnostics, are Wi-Fi and voice-recognition capably for enhanced comfort and convenience. 

Looking at the above features and specs, including the customer reviews, likes and dislikes, this is our selection of the top three models; Rinnai RL94, Noritz NR98, and Takagi T-K4.

And for those who would like more, condensing models, are what you should look for, as explained in this review.


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