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A Navien tankless water heater is a common pick for high-efficiency condensing gas hot water. Here’s how the NPE lineup works and what to know before buying.
Navien is part of KD Navien, a South Korean manufacturer, with U.S. headquarters in California. It is known for high-efficiency condensing gas products: tankless water heaters, combi boilers and boilers. Navien was an early adopter of PVC-vented condensing tankless designs and of built-in recirculation in residential tankless units.
A Navien hot water heater today usually means a Navien water heater tankless model from the NPE series, a Navien gas tankless water heater for natural gas or propane.
| Model | Max input (approx.) | Typical use |
|---|---|---|
| NPE-150 | 120,000 BTU | Smaller homes, warm climates |
| NPE-180 | 150,000 BTU | 1–2 bathrooms |
| NPE-210 | 180,000 BTU | 2–3 bathrooms |
| NPE-240 | 199,900 BTU | 3+ bathrooms or cold climates |
Each model comes as an A2 (with ComfortFlow buffer tank and recirculation pump) or S2 (standard). The NPE-240A2 is one of the most popular whole-house units in the U.S. Check the spec sheet for flow at your temperature rise.
A2 models’ small buffer tank smooths out the cold-water sandwich effect, and the built-in pump supports recirculation with an external dedicated return line or, on some setups, a crossover valve. Recirculation can run on a schedule or on demand. See our recirculation pump guide.
Navien NCB combi boilers heat your home (radiators or radiant floors) and provide on-demand domestic hot water from one wall-hung unit. They suit homes with hydronic heating. See tankless boilers and combi units.
Flush annually and clean the cold-water inlet filter. Common codes include E003 (ignition failure), E012 (flame loss) and E110 (exhaust or air supply problem). Flow sensor faults can cause the unit not to fire. See our error codes guide and how to flush a tankless water heater.
Navien units are mid-to-premium priced. The A2 version costs more than S2 but adds recirculation and buffer-tank comfort. Compare with Rinnai and other picks in our best tankless water heaters guide.
Navien tankless water heater price depends on size and version; the Navien water heater cost installed is similar to other premium condensing brands. Read Navien tankless water heater reviews from verified buyers and installers before deciding.
See current Navien listings with condition, specs and price.
A2 models include a small internal buffer tank and recirculation pump (ComfortFlow), which reduce temperature swings and support recirculation. S2 models are the standard version without them and cost less.
Navien NPE units typically cost roughly $1,100–$2,500 for the unit depending on size and A2 or S2 version, plus installation. Check current prices on product pages.
Navien publishes installation and user manuals for each model on its website. Search your exact model number, such as NPE-240A2.
Navien is focused on gas and propane products in the U.S. For electric tankless options, see our electric tankless water heaters.
Residential NPE-2 units typically carry a long heat exchanger warranty, often up to 15 years, with shorter parts and labor coverage. Terms depend on installation and registration; check Navien’s current warranty document.
This guide is general information for U.S. homeowners, not professional advice. Gas, electrical and venting work must follow the manufacturer’s instructions and local codes, and in most areas requires a licensed plumber, electrician or gas fitter and a permit. Specifications and prices change; always confirm details on the product page and in the installation manual.
