Navien NPE-240A Tankless Water Heater Review is reader-supported. As an Amazon affiliate, we earn from qualifying purchases.Learn more

Navien is a subsidiary of KyungDong Navien (KD Navien), which was founded in 1978.

Navien has its North American headquarters at Irvine, California. Navien ranks first in technology patents and has the largest market share in condensing water heaters in North America.

The Navien NPE-240A is a high efficiency condensing tankless water heater that uses propane or natural gas to heat water.

Its dual stainless steel heat exchangers and ComfortFlow technology help reduce the wait time for hot water and have almost no temperature fluctuations.

Navien NPE-240A Specifications Table 

The specifications for Navien NPE-240A are as follows – 

Parameters Specifications
Natural gas 19,900 - 199,900 BTU/H (5.831 - 58.571 kWh)
Liquid propane 19,900 - 199,900 BTU/H (5.831 - 58.571 kWh)
UEF (natural gas and liquid propane) 0.96
EF (Canada natural gas and liquid propane) 0.97
35°F temperature rise 11.2 GPM (42.4 l/m)
45°F temperature rise 8.7 GPM (32.9 l/m)
67°F temperature rise 5.6 GPM (21.2 l/m)
Dimensions 17.3" W x 27.4" H x 13.2" D (43.9cm W x 69.6cm H x 33.5cm D)
Boiler weight 82 lbs. (37.2 kg)
Installation type Indoor Wall hung
Installation type Outdoor Wall hung
Venting type Forced draft direct vent
Ignition Electronic ignition
Natural gas supply 0.87kPa to 2.61kPa
Propane gas supply 1.99kPa to 3.23kPa
Natural gas manifold pressure -0.0124kPa to -0.144kPa
Propane gas manifold pressure -0.0249kPa to -0.194kPa
Minimum flow rate 0.5GPM
Cold Water Inlet ¾ in.
Hot Water Outlet ¾ in.
Main supply 120V AC, 60 Hz
Maximum power 200W (max 2A) or 350W (max 4A) with an external pump
Materials used for Casing Cold rolled carbon steel
Materials used for Heat exchanger Stainless steel
Venting for Exhaust 2" or 3" PVC, CPVC, polypropylene / 2" or 3" special gas vent type BH (Class II, A/B/C)
Venting for Air intake 2" or 3" PVC, CPVC, polypropylene / 2" or 3" special gas vent type BH (Class II, A/B/C)
Venting for Vent clearances 0" to combustibles


Image Source: Company Website

Installing the NPE-240A tankless water heater is quite simple and explained in detail in the installation manual provided with the product.

While installing the heater, follow the steps mentioned by the manufacturer carefully to avoid any damages.

Choosing the right location, careful mounting of the product, the meticulous connection of the pipelines, connecting the condensate drain and venting are the initial procedures for installation.

The final step is to connect the power supply and set the DIP switches.

Ensure that the factory settings of the product remain unchanged while installation.


Navien NPE-240A and other advanced series water heaters by Navien come with a limited warranty that covers labor, parts, and the heat exchanger.

The warranty period starts from the date of installation.

For NPE-240A tankless water heaters used for residential applications, the warranty periods that are applicable are as follows.

Labor (in years) Parts (in years) Heat exchanger (in years)
Standard or controlled recirculation produced on or after Jan 1, 2016. 1 5 15
Uncontrolled recirculation produced on or after Jan 1, 2016. 1 3 5
Units produced before Jan 1, 2016. 1 5 15

For NPE-240A tankless water heaters used for commercial applications and used as combination water and space heaters, the warranty periods are as follows.

Labor (in years) Parts (in years) Heat exchanger (in years)
Standard or controlled recirculation produced on or after Jan 1, 2016. 1 5 8
Standard or controlled recirculation produced before Jan 1, 2016. 1 3 10
Uncontrolled recirculation 1 3 3

Controlled recirculation is when the recirculation of water is controlled by the heater or an external aquastat. Uncontrolled recirculation is when external pumps are used to circulate water continuously to the heater.

Any defective components will be replaced by Navien if prior to the expiration of the warranty periods. The replaced component will have a warranty period equal to that of the remaining warranty period of the original product.

The warranty does not cover replacement of the components in case any of the following events occur.

  • If the Navien NPE-240A tankless water heater was purchased from any second party or agent not authorized by Navien or if the installation was done improperly.
  • If any damage to product is inflicted intentionally or due to improper maintenance.
  • If a manufacturing defect is not directly responsible for any damage to the product
  • If the heater malfunctions due to usage of any other fuel that is not specific to the water heater.
  • Not using potable water or using the heater for non-recommended purposes.
  • Not adhering to the limits as shown in the rating plate, or removal or altering the rating plate.
  • Installation in a country apart from the United States and Canada.

To claim the warranty, contact the original installer of your product or Navien’s Technical Administration Department at (800) 519-8794. In order to obtain warranty, proof of purchase and date of installation are necessary.

Care and Maintenance

Maintenance of NPE-240A tankless water heater has to be done regularly like any other water heater.

Maintaining the water heater includes keeping the heater clean and ensuring the heater is not subjected to extreme conditions.

Flushing has to be done regularly to prevent excessive mineral build-up. Cleaning the water filter and the air intake filter must be done every 3 – 4 months for proper maintenance of the water heater.

This product is stress and corrosive tolerant but do not expose it too much of these conditions.

Consumer Comments

Navien NPE-240A is a user-friendly product with great features that can be understood by the user easily.

One of its unique features that have received a positive response from customers is the ‘Navilink’ app that allows the users to control the heater from their mobile phones.

Users have found it easier to configure temperature settings in this heater because, instead of a knob to control the water temperature, this water heater comes with arrowheads present in the front panel that help set the temperature precisely.

It has a massive flow rate of a little over 12 gallons per minute, making it ideal for large homes and even for small commercial applications.

Most people who have bought this product agree with being able to use simultaneous applications with a single heater.

Although the advantages and benefits of this tankless water heater are quite unmatched, the high cost of this product has caused many users to turn away from this product.



  • It emits very low amounts of nitrogen oxides (around 20 ppm).
  • The heater is highly tolerant to mechanical, thermal stress, and even corrosive substances to an extent.
  • It has an incredible level of energy efficiency of 97%.
  • It has a very high flow rate.
  • It has an advanced preheating technology that increases efficiency as well as eliminate the ‘cold water sandwich effect’.


  • NPE-240A is much more expensive than other tankless water heaters with lower flow rates and minimal features. It is also comparatively bigger in size than most other tankless water heaters.

Our Recommendation

Navien NPE-240A tankless water heater is perfect for households located in extremely cold areas and large homes with a lot of people using hot water fixtures at the same time.

Unlike other tankless water heaters, it is capable of providing continuous water heaters for at least four applications at the same time.

However, it is impractical to spend a lot of money on a water heater if it is to be used in a household of one or two. It is also not recommended to install this water heater for point-of-use applications.

Recommended Accessories

Flow Sensor Required at the Inlet of the Heater

Navien Flow Sensor Tankless Water Heater


Neutralizers to Neutralize the Condensate

Navien GXXX001322 Residential Neutralizer Kit


Front Panel Kit with NaviLink Wi-Fi Upgrade Navien 30008333D Npe Front Panel Kit for Navilink WiFi Upgrade



What does the ‘A’ in NPE-240A Stand for?

The ‘A’ in the name of the product stands for advanced. It is to specify the advanced preheating technology present in this product.

How do I deal with the Installation Process and Support from the Manufacturer?

The installation process is quite simple and can be done by the users themselves. To deal with any technical issues, the technical support details provided by the manufacturer are specified in the user manual.

Is there a Warranty for the Product?

Yes. Check the Navien website or the user manual of the product for details regarding warranty.

What is the Temperature Range?

The temperature is commonly set between 120˚F to 140˚F. If the water heater is being used in commercial mode, the temperature can be set as high as 180˚F.

Our Recommendation

Navien NPE-240A is a highly efficient tankless water heater that has an enormous output flow rate.

It comes with various advanced features that are user-friendly and overcome the limitations present in other tankless water heaters.

However, one must carefully evaluate the benefits of this product and purchase it only if it is absolutely necessary. If installed in locations where it cannot be used optimally, the payback from this product will be very minimal.

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