5 Best Navien Tankless Water Heaters in 2021 – Reviews and Buyer’s Guide

It’s quite evident that water heaters have become a necessity rather than a luxury in today’s world. Running out of hot water during showers and everyday chores is a terrible experience for all of us. Therefore, it is always better to invest in a high-quality tankless water heater that provides a continuous supply of hot water on demand.

If you’ve come across the trouble of running out of hot water and are searching for a premium tankless water heater, it is quite evident that you might have come across Navien Tankless Water Heaters. There are hardly any brands in the market that come close to competing with this brand when it comes to quality, performance, durability, and energy efficiency.

There is no doubt that Navien is among the world’s top brands for tankless water heating systems. Since the introduction of their first heating appliance in 1978, they have flourished to become the first Asian company to manufacture high performing and environmentally-friendly water heating units.

After significant expansion around a decade ago, Navien has become one of the most reputable and fastest-growing companies across the world. They’ve claimed their stature for manufacturing some of the best tankless models in the market with advanced features, high performance, and energy efficiency, it is rightly so.

If you take a look around the market, you’ll find plenty of models that are suitable for different purposes. Having to choose the most suitable model for your home might be a challenging task. Therefore, to help you overcome the complications, we’ve reviewed five of the best tankless water heaters manufactured by Navien.

Along with the detailed review, we have also illustrated a comparison chart of all the reviewed models and also included some Frequently Asked Questions on Navien tankless water heaters.

So, without further ado, let’s dive into it!

Our Top Pick

Navien NPE-240S Condensing Tankless Water Heater

With plenty of tankless water heaters available in the market, it might be a hassle to find the best one among them. However, if you’re looking for a premium tankless unit, we recommend you to go for Navien NPE-240S Condensing Tankless Water Heater.

With a maximum flow rate of 11.2 gallons per minute, this water heater is an absolute beast for a tankless unit. Unlike conventional tank-style units, this water heater offers far more superior energy factors due to reduced vent temperatures.

In addition, this water heater includes two top-graded stainless steel heat exchangers for high efficiency and quick recovery. The Eco Premixed Burner encourages an eco-friendly lifestyle as it minimizes the CO and NOx emissions by combining air and gas heating prior to ignition.

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Quick Summary of Best Navien Tankless Water Heaters

Product Image Product Name
Top Pick for Overall Performance
Navien NPE-240S Condensing Tankless Water Heater

Designed to deliver excellent performance, the NPE-240S is certainly Navien’s most premium water heater in the market. With a massive flow rate of 11.2 GPM, this water heater is more than enough to accommodate a large household with a high demand for hot water. The advanced condensing technology of this water heater secures the extra heat loss for fast heating and quick recovery.

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Tankless Water Heater with High Flow Rate
Navien NPE-240A Condensing Tankless Water Heater

Compact, powerful, and well-built, the NPE-240A is the highest-selling model by Navien. It also has the capacity to supply hot water at the rate of 11.2 GPM, which is ridiculously high for a tankless water heater. Similarly, it also ensures a powerful and consistent performance with the maximum input capacity of 199900 BTU per hour.

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Water Heating System with Industry High Warranty
Navien NPE-210A Condensing Tankless Water Heater

Navien NPE-210A is an excellent choice for a medium-sized family that has a decent requirement for hot water. With 10.2 GPM flow rate, this model guarantees to deliver a constant supply of hot water. Additionally, it also features a built-in internal buffer tank, which means you no longer have to be concerned about running out of hot water.

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Best Value for Money
Navien NPE-180S Condensing Tankless Water Heater

The NPE-180S is one of the most economical tankless water heaters manufactured by Navien. Even though this unit is budget-friendly, the manufacturers have not compromised in the quality of the unit. It has a maximum flow rate of 8.4 GPM, which is up to the mark to accommodate small to medium households.

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Top Pick for Budget-Friendly Water Heater
Navien NPE-150S Condensing Tankless Water Heater

The NPE-150S is the most inexpensive tankless water heater on this list. But, the performance and quality of this unit are truly commendable. With a flow rate of 6.8 GPM, this water is ideal for a small family that does not require excessive hot water. In addition, this water heater also features a digital front control panel, which is a rare feature for units at this price range.

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Best Navien Tankless Heaters of 2021 - Reviewed

Comparison Table for Navien Tankless Water Heaters

SNProduct NameDimensions (inches)Shipping Weight (pounds)Maximum Flow Rate (GPM)Heat Exchanger MaterialCasing MaterialIgnition
1Navien NPE-240S Condensing Tankless Water Heater17.0 x 27.4 x 13.27511.2Stainless SteelCold Rolled Carbon SteelElectronic
2Navien NPE-240A Condensing Tankless Water Heater 17.0 x 27.4 x 13.28211.2Stainless SteelCold Rolled Carbon SteelElectronic
3Navien NPE-210A Condensing Tankless Water Heater17.0 x 27.4 x 13.28210.1Stainless SteelCold Rolled Carbon SteelElectronic
4Navien NPE-180S Condensing Tankless Water Heater17.0 x 27.4 x 13.2678.4Stainless SteelCold Rolled Carbon SteelElectronic
5Navien NPE-150S Condensing Tankless Water Heater17.0 x 27.4 x 13.2556.8Stainless SteelCold Rolled Carbon SteelElectronic

FAQs on Navien Tankless Water Heaters

Yes, you can install a ½ inch gas pipe with the NPE condensing water heater as long as you connect the pipe appropriately. There are plenty of factors such as pipe size, length of pipe, and pressure drop, that affects the gas delivery. It is always better to refer to the gas pipe sizing table of National Fuel Gas Code to ensure if you have a sufficient supply of gas for your water heater.

No, the NPE tankless water heater doesn't need to be the first appliance of the gas meter. You can always install the unit using the existing infrastructures. It can even go in place of conventional tank-type water heaters as long as the gas line is capable of delivering sufficient supply of gas to the unit and is sized properly.

It is recommended that you vent the NPE water heater with a 2-inch vent component. However, you can also use a 3-inch vent material if you prefer it instead of the 2-inch vent. The approved vent components for NPE condensing tankless units are CPVC Schedule 80, PVC Schedule 40, and Approved Polypropylene.

ComfortFlow Technology is an innovative proprietary system that incorporates a recirculation pump and buffer tank in the water heater. A buffer tank basically helps to reduce the ‘cold water sandwich’ effects, which are common issues in tankless water heaters. Likewise, the recirculation pump helps to reduce the amount of time that is required for a unit to deliver hot water to fixtures.

Yes, you can mount the Navien tankless water heaters outdoors by using the brand exclusive Navien Outdoor Vent Kit. However, we recommend you mount the water heaters outdoors only in mild climates. Also, you should follow proper instructions according to the manual while installing the water heater outdoors.

Yes, all the Navien tankless water heaters are gas field convertible. The default gas type of the NPE water heaters will be natural gas (NG). If you choose to convert the gas type into LP use, you can use the gas conversion kit that comes along while purchasing the water heater. However, it is recommended to convert the gas field with the help of a qualified service agency.


There you go! That’s all regarding the 5 best Navien Tankless Water Heaters available in the market today. No matter which Navien product you decide to buy, all these water heaters are guaranteed to deliver excellent performance and serve for an extended period of time.

As one of the best brands for tankless water heaters, Navien not only considers performance as their key factor but also opts for energy efficiency for sustainable use. For your convenience, we have mentioned explicit tankless water heater buying guide on our next article.

In Hurry? Editor's Choice
Navien NPE-240S Condensing Tankless Water Heater