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Comparison
Verdict in brief
Both are wall-hung, forced-draft direct-vent condensing tankless units from Navien's Canadian A2 platform with UEF 0.95, the same 27.4 in cabinet and the same 2 in or 3 in PVC-family venting. The NPE-180A2 is 10,000–150,000 BTU/h and the NPE-210A2 is 12,000–180,000 BTU/h. The practical difference is published flow at a cold-water rise: 4.3 GPM against 5.1 GPM at a 67 °F rise. For one fixture at a time the NPE-180A2 fits; for two simultaneous showers in a Metro Vancouver winter, the NPE-210A2 is the more honest starting point.
Published manufacturer figures with units. Storage and flow figures are different measures and are shown on their own rows; blanks mean not applicable or not published.
| Specification | Navien NPE-180A2Gas tankless | Navien NPE-210A2Gas tankless |
|---|---|---|
| Minimum gas input | 10,000 BTU/h | 12,000 BTU/h |
| Maximum gas input | 150,000 BTU/h | 180,000 BTU/h |
| Flow at a 35 °F (19.4 °C) rise | 8.4 GPM (31.8 L/min) at 35 °F (19.4 °C) rise | 10.1 GPM (38.2 L/min) at 35 °F (19.4 °C) rise |
| Flow at a 45 °F (25 °C) rise | 6.5 GPM (24.6 L/min) at 45 °F (25 °C) rise | 7.8 GPM (29.5 L/min) at 45 °F (25 °C) rise |
| Flow at a 67 °F (37.2 °C) rise | 4.3 GPM (16.3 L/min) at 67 °F (37.2 °C) rise | 5.1 GPM (19.3 L/min) at 67 °F (37.2 °C) rise |
| Minimum flow rate | 0.5 GPM (1.9 L/min); under 0.01 GPM option in ComfortFlow mode | 0.5 GPM (1.9 L/min); under 0.01 GPM option in ComfortFlow mode |
| Uniform Energy Factor (UEF) | 0.95 | 0.95 |
| Vent type | 2 in or 3 in PVC, CPVC, approved polypropylene or stainless steel; special gas vent type BH (Class II A/B/C) | 2 in or 3 in PVC, CPVC, approved polypropylene or stainless steel; special gas vent type BH (Class II A/B/C) |
| Gas connection | 3/4 in | 3/4 in |
| Water connections | 3/4 in cold inlet and hot outlet | 3/4 in cold inlet and hot outlet |
| Electrical supply | 120 V AC, 60 Hz; up to 200 W (2 A), 350 W (4 A) with external pump | 120 V AC, 60 Hz; up to 200 W (2 A), 350 W (4 A) with external pump |
| Height | 27.4 in (696 mm) | 27.4 in (696 mm) |
| Width | 17.3 in (439 mm) | 17.3 in (439 mm) |
| Depth | 13.2 in (335 mm) | 13.2 in (335 mm) |
| Weight | 73 lb (33.1 kg) | 77 lb (34.9 kg) |
| Maximum altitude | 10,100 ft for natural gas and propane | 10,100 ft for natural gas and propane |
“—” means not applicable to that system type or not published by the manufacturer. Flow figures are only comparable at the same temperature rise; UEF values are only comparable within the same draw pattern.
Navien publishes flow at three temperature rises, which makes the A2 range unusually easy to compare honestly. At a 35 °F (19.4 °C) rise the NPE-180A2 delivers 8.4 GPM (31.8 L/min) and the NPE-210A2 10.1 GPM (38.2 L/min); at 45 °F (25 °C) it is 6.5 against 7.8 GPM; and at 67 °F (37.2 °C), the figure closest to a Metro Vancouver winter rise to a 49 °C shower, it is 4.3 GPM (16.3 L/min) against 5.1 GPM (19.3 L/min). Those at-rise numbers, not the warm-inlet maximum, are what decide whether a second fixture can run.
Input and modulation follow the same split. The NPE-180A2 modulates from 10,000 to 150,000 BTU/h and the NPE-210A2 from 12,000 to 180,000 BTU/h. The NPE-180A2 therefore turns down lower for small draws but tops out 30,000 BTU/h sooner, and its 73 lb (33.1 kg) cabinet is the lighter of the two against 77 lb (34.9 kg) for the NPE-210A2. Both share UEF 0.95, the same 120 V electrical requirement (up to 200 W, 350 W with an external recirculation pump), and the same 3/4 in gas and water connections.
Venting and installation are identical across the A2 platform: 2 in or 3 in PVC, CPVC, approved polypropylene or stainless steel, or a BH special gas vent, terminated as a forced-draft direct vent with zero clearance to combustibles, plus a condensate drain. Both support Navien's ComfortFlow recirculation with an external pump or crossover valve rather than a built-in pump, and both are subject to Navien's published policy voiding warranty on internet or e-commerce purchases, so supply runs through contractors.
The choice is therefore demand-driven rather than feature-driven. A one-bathroom home or suite with sequential use fits the NPE-180A2; a two-bathroom home that expects occasional overlap in January should start from the NPE-210A2, and if overlap is routine, from the larger NPE-240A2. The demand assessment measures simultaneous flow and confirms the gas supply and vent route before a model is specified, and whether CANRO supplies a given A2 model for a job is confirmed at consultation.
Navien · Gas tankless
The Navien NPE-180A2 is the smallest of Navien's Canadian A2 condensing tankless models: 10,000–150,000 BTU/h on natural gas or propane, UEF 0.95, and published flows of 8.4 GPM at a 35 °F rise and 4.3 GPM at a 67 °F rise. It is a wall-hung, forced-draft direct-vent unit.
Navien · Gas tankless
The Navien NPE-210A2 is the middle of Navien's Canadian A2 condensing tankless models: 12,000–180,000 BTU/h on natural gas or propane, UEF 0.95, and published flows of 10.1 GPM at a 35 °F rise and 5.1 GPM at a 67 °F rise. It is a wall-hung, forced-draft direct-vent unit.
At its published 67 °F-rise rating of 4.3 GPM (16.3 L/min) it cannot serve two shower-class fixtures at once in January. The NPE-210A2's 5.1 GPM at the same rise is marginal; a routine two-shower overlap points to the NPE-240A2.
No. Navien rates both at UEF 0.95 for natural gas and propane. The difference is capacity, not efficiency, and the UEF is a high-draw-class rating, not a savings percentage.
No. Both use the A2 platform's 2 in or 3 in PVC, CPVC, approved polypropylene or stainless venting (or BH special gas vent) as a forced-draft direct vent, with the same 3/4 in gas connection and a condensate drain.
A consultation includes a hot-water demand review so capacity is right for your winter, not the brochure's.
On-site service in Metro Vancouver, BC. Call to check availability.
Sources and verification
Facts checked September 21, 2026. Last updated September 21, 2026. Technical reviewer: not yet assigned.