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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-240A2 is 13,300–199,900 BTU/h and the NPE-180A2 is 10,000–150,000 BTU/h. Navien publishes flow at three rises, and at the 67 °F figure closest to a Metro Vancouver winter the pair delivers 5.6 GPM against 4.3 GPM: the 180A2 is a one-fixture-at-a-time unit in January, and the 240A2 is marginal for two. Choose by peak simultaneous demand, not by house size.
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-240A2Gas tankless | Navien NPE-180A2Gas tankless |
|---|---|---|
| Minimum gas input | 13,300 BTU/h | 10,000 BTU/h |
| Maximum gas input | 199,900 BTU/h | 150,000 BTU/h |
| Flow at a 35 °F (19.4 °C) rise | 11.2 GPM (42.4 L/min) at 35 °F (19.4 °C) rise | 8.4 GPM (31.8 L/min) at 35 °F (19.4 °C) rise |
| Flow at a 45 °F (25 °C) rise | 8.7 GPM (32.9 L/min) at 45 °F (25 °C) rise | 6.5 GPM (24.6 L/min) at 45 °F (25 °C) rise |
| Flow at a 67 °F (37.2 °C) rise | 5.6 GPM (21.2 L/min) at 67 °F (37.2 °C) rise | 4.3 GPM (16.3 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 | 77 lb (34.9 kg) | 73 lb (33.1 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's at-rise flow table makes this comparison unusually honest. At a 35 °F (19.4 °C) rise the NPE-240A2 delivers 11.2 GPM (42.4 L/min) and the NPE-180A2 8.4 GPM (31.8 L/min); at 45 °F (25 °C) it is 8.7 against 6.5 GPM; and at 67 °F (37.2 °C) it is 5.6 GPM (21.2 L/min) against 4.3 GPM (16.3 L/min). Because heating Metro Vancouver's winter inlet water to a 49 °C shower is roughly a 40 °C (72 °F) rise, the 67 °F row is the one that decides whether a second shower can run alongside the first.
Input and modulation track the size gap. The NPE-240A2 modulates from 13,300 to 199,900 BTU/h; the NPE-180A2 from 10,000 to 150,000 BTU/h. The smaller unit therefore turns down lower for a single low-flow tap but tops out 49,900 BTU/h sooner. The NPE-240A2 is also the heavier cabinet at 77 lb (34.9 kg) against 73 lb (33.1 kg), though both share the same 27.4 in × 17.3 in × 13.2 in dimensions.
Everything else in the platform is common: UEF 0.95 on natural gas and propane, 3/4 in gas and water connections, 120 V power drawing up to 200 W (350 W with an external pump), the same 2 in or 3 in PVC, CPVC, approved polypropylene or stainless venting (or BH special gas vent) terminated as a forced-draft direct vent with zero clearance to combustibles, a condensate drain, and ComfortFlow recirculation through an external pump or crossover valve rather than a built-in pump. Both are rated to 10,100 ft altitude and both are subject to Navien's published policy voiding warranty on internet or e-commerce purchases.
The middle NPE-210A2 sits between them and is documented separately. In practice 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 or NPE-240A2 rather than the entry size. A 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-240A2 is the largest of Navien's Canadian A2 condensing tankless models: 13,300–199,900 BTU/h on natural gas or propane, UEF 0.95, and published flows of 11.2 GPM at a 35 °F rise and 5.6 GPM at a 67 °F rise. It is a wall-hung, forced-draft direct-vent unit.
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.
No. It is 33% more input (199,900 against 150,000 BTU/h) and 30% more flow at the winter-class rise (5.6 against 4.3 GPM at 67 °F). It buys simultaneous capacity, not more hot water for a single fixture.
Only if the bathrooms are used sequentially. At its published 67 °F-rise rating of 4.3 GPM it cannot carry two shower-class fixtures at once in a Metro Vancouver winter; overlapping use points to the NPE-210A2 or NPE-240A2.
No. Both use the A2 platform's 2 in or 3 in PVC, CPVC, approved polypropylene or stainless venting (or BH special gas vent), a 3/4 in gas connection and a 120 V outlet, with a condensate drain for the acidic condensate.
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.