Navien NPE Water Heaters: Review and Buying Tips

Navien NPE-240 water heaterNavien NPE-240
(photo: amazon)

Discover Navien tankless and condensing water heaters from the NPE series with the standard and advanced groups of heaters made for on-demand heating of potable water in residential and light commercial applications, including space heating. Check out the main differences between NPE-A and NPE-S models and which is a better buy.

Navien NPE series: Models and features review

The Navien NPE series comprises two types of tankless and condensing water heaters; NPE-A as the advanced and NPE-S as the standard type. NPE-A has three models to choose from; NPE-180, NPE-210, and NPE-240, while the NPE-S group includes one more, NPE-150S, as the smallest unit in this group.

ComfortFlow technology

All models coming from the Navien NPE-A group are equipped with the ComfortFlow technology, a technology that reduces the wait time for hot water between the heat exchanger and hot water tap, eliminates the minimum flow rate requirement, and reduces the temperature fluctuation.

This is what increases the overall experience and saves you money. The ComfortFlow technology of the NPE-A models incorporates the recirculation pump and 0.4 gallons buffer tank, ensuring fast delivery of hot water and reducing the number of "cold water sandwich" effects. By setting up the DIP switch, you can arrange any model to use the internal or external recirculation mode.

Advanced control panel

In front of the Navien NPE water heaters is the control panel that includes features such as hot water recirculation mode, diagnostic button, a master button for cascade operation, a button for basic information, power and reset button, up and down button to increase and decrease the temperature and status light. 

Using the up and down push buttons, the temperature can be set in 1 F increment, in the range from 98 F to maximum 140 F, while NPE-240A and space heating up to 185 F. A remote controller can also be installed, but it is an optional accessory.

Ultra high efficiency

Both groups are equipped with two stainless steel heat exchangers, made to heat water fast, efficiently, and for many years.

NPE-A models have an energy factor of up to 0.97, while the NPE-S has a maximum EF of 0.99. This ensures excellent energy savings as it can heat water more efficiently and with less power than the non-condensing units.


Every unit must be adequately vented to ensure the constant flow of fresh air for combustion and removal of the products of combustion. For the proper work of the venting system, NPE uses the 2" PVC, PP, ABS or CPVC venting pipes with the maximum length of 60 ft, and if the 3" pipe is used, up to 150 ft.

More hot water with the cascading system

Another great advantage of the Navien NPE water heaters is the built-in control feature for the multi-unit system, so no extra elements and features are needed for cascading units into one system. Up to 16 units can be connected via Navien Ready-Link communication cable if demand for hot water is high.

Useful add-on features

The NPE series are made for water heating and combined space / DHW application. An add-on controller allows NPE-A models and hydronic air handlers to work together, utilizing the pump to circulate hot water.

Another useful add-on feature is the Wi-Fi remote control system, which allows users with the smartphone to remotely control water temperature, check the status, and  if there is a malfunction - receive diagnostic error codes.


Models / Specs NPE-150S NPE-180A/S NPE-210A/S NPE-240A/S
Gas input (BTU) 18,000-120,000 15,000-150,000 19,900-180,000 19,900-199,900
Water flow (GPM)
(@35 F temp.rise)
6.8 8.4 10.1 11.2
Energy factor 0.97 0.97
Temp. settings (F) 98-140 98-140 98-140 98-140
Energy consumption (Watts) 200 200 200 200
Max. vent length (ft) 2" - up to 60 2" - up to 60 2" - up to 60 2" - up to 60
Size (inch) 17.3 x 27.4 x 13.2
Weight (lbs) 55 75

Features review

  • Primary and secondary heat exchangers, made of stainless steel for reliable and long-lasting heating operation.
  • Indoor and outdoor installation where the indoor model uses direct vent sealed combustion while the outdoor is ventless.
  • Built-in control panel for temperature control and error code display.
  • Cascading set-up for connecting up to 16 units.
  • Built-in pump and buffer tank for internal and external recirculation in Navien NPE-A series.
  • Intelligent Preheating Technology recognizes hot water usage patterns, increasing comfort and saving energy.
  • All Navien NPE models are factory built to use natural gas and convert to use propane gas.
  • Safety features: Flame Rod, APS, Ignition Operation Detector, Water Temperature High Limit Switch, Exhaust Temperature High Limit Sensor, Power Surge Fuse. The freeze protection uses the recirculation mode to protect the unit.
  • Warranty of 15 years on heat exchangers.

Navien tankless and condensing water heaters from the NPE series are powerful and versatile units that can last for many years (approximately 20 years) and be properly maintained and serviced on time. The manufacturer provides a warranty of 15 years in residential applications and 8 in the commercial on the heat exchanger.

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