Best Condensing Tankless Water Heaters

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The best condensing tankless water heaters article reviews the top manufacturers in water heating industry Noritz, Rinnai and Navien and includes the most advanced features and benefits condensing technology brings.

Condensing water heaters are the most energy efficient gas heaters that are available today. They utilize two exchangers; one that gets the heat directly from the gas burner and the other which is made of stainless steel that uses the residual heat from the flue gases (wasted energy). This is what increases the performance and efficiency while significantly reduces the emission of the greenhouse gases and saves on energy.

Since the flue gases are cooled down, every condensing water heater can use cheaper venting, usually made of PVC material, vs. more expensive stainless steel for non-condensing units. The review of the best tankless brands and models, can be found here.

Rinnai condensing tankless water heaters

rinnai condensing rc98

Rinnai offers two condensing tankless water heaters; RC98i model which is designed for an indoor and RC98e for the outdoor installation. 

An indoor RC98i model operates with the forced, sealed combustion so the flue gases are safely moved out and fresh air sucked in.

Both models are coming from the Ultra line series and have energy efficiency of up to 96% making them Energy Star compliant and eligible for rebates.

RC98 water heaters, with its maximum flow of 9.8 gallons per minute, provide enough hot water for larger homes and families with a high hot water demand. On the other side low flow of 0.4 GPM is enough for heater activation and if you need smaller amount of water, for shaving, for example.

These models are approved for both natural and propane gas and thanks to the modulation in gas valve they can provide power from the minimum 9,500 to maximum of 199,000 Btus per hour.

Provided digital controller allows temperature change from 98 F to 140 F in residential applications or up to 185 F with the commercial controller.

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Noritz condensing water heaters

noritz condensing nrc111

The best of Noritz condensing tankless water heaters is coming from NRC111 series, a series with the amazing 11.1 GPM flow. Such a high water flow accommodates high demanding homes, with up to three showers working simultaneously, while its capability to be combined with the identical water heater through the Quick-Connect brings the twice as much hot water.

Both indoor NRC111-DV and outdoor NRC111-SV are equipped with the dual flame burners for less fluctuation in the temperature and commercial grade heat exchangers with a thicker piping, making it very resistant to stress and abuse.

The minimum water flow is higher (0.5 GPM) than the upper Rinnai models, while the maximum flow is higher.

Navien condensing water heaters

Navien NP-240

Navien condensing tankless water heaters are the most efficient heaters in this group. The energy efficiency they are providing is amazing 98%, and thanks to the Eco Three-phased Pre-mixed burner they reduce NOx emission drastically.

Navien utilizes two heat exchangers, both made of stainless steel which makes them more resistant to stress while providing longer life. The warranty is longer than on other brands, it is 15 years on the heat exchanger, vs. 12 on other brands.

With the two microprocessors Navien provides better control and safety while optimizing the best performance and giving its users hot water temperature with much less fluctuation.

Navien NP-240 is the tankless water heater with the highest flow from this manufacturer, 11 GPM, and with the Ready Link System it connect 16 units into one system, which makes it ideal for large volumes of hot water.

Another great benefit Navien offers is the air and gas pressure sensor which maximizes combustion efficiency while making the combustion stable.

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Condensing tankless water heaters are getting more and more on popularity because of the green technology and many advantages they offer. Designed as the next generation in tankless technology, their advanced technology brings the extremely high efficiency, high performance level, less gas emission and energy savings.

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Rinna RUR98I won't circulate at set point Not rated yet
I have (2) Rinnai RUR98I units installed on 6/23/16. Neither will circulate water at temp set point. They run 15 to 20 degrees under set point .. 120 is …

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