Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
Both first-generation NCB combis share the same 17 x 28 x 12 in wall-hung cabinet and 3/4" connections, but the NCB-210 raises the heating ceiling from 80 to 100 MBH, DHW input from 150,000 to 180,000 BTU/h and DHW flow from 3.4 to 4.0 GPM at a 77°F rise — at 10 lb more weight and a slightly higher 93.6% AFUE against the NCB-180's 93.5%.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Navien NCB-180 | Navien NCB-210 |
|---|---|---|
| Heating input, minimum | 14 MBH | 18 MBH |
| Heating input, maximum | 80 MBH | 100 MBH |
| Heating capacity | 74 MBH | 92 MBH |
| Net AHRI water rating | 64 MBH | 80 MBH |
| Efficiency (AFUE) | 93.5 % | 93.6 % |
| DHW input, maximum | 150 MBH | 180 MBH |
| DHW flow rate at 77°F (43°C) rise | 3.4 GPM | 4 GPM |
| Weight | 74 lb | 84 lb |
The NCB-180 and NCB-210 are the first two models of Navien's original NCB combi series. The NCB-180 fires 14 to 80 MBH for space heating with a 74 MBH capacity and a 64 MBH net AHRI water rating at 93.5% AFUE; the NCB-210 fires 18 to 100 MBH with a 92 MBH capacity, an 80 MBH net rating and 93.6% AFUE, per the NCB Installation and Operation Manual.
The hot-water side steps up too: DHW input rises from 150,000 to 180,000 BTU/h and the published flow at a 77°F (43°C) rise from 3.4 to 4.0 GPM, so the 210 supports a heavier draw or a colder incoming-water season. Both models share the 0.5 GPM minimum DHW flow, 1" NPT heating connections, 3/4" NPT DHW and gas connections and 2"/3" venting options.
Physically the difference is modest: the NCB-180 weighs 74 lb against the NCB-210's 84 lb, both in the same 17 x 28 x 12 in cabinet. Because the series is discontinued, the comparison is mainly useful for owners matching an existing unit or judging whether a replacement should follow the 210-class ceiling; the current equivalents are the NCB-H models.
Navien
The Navien NCB-180 is a first-generation wall-hung condensing combi from the discontinued NCB series: 14 to 80 MBH of heating input with 74 MBH heating capacity, 93.5% AFUE and DHW input to 150,000 BTU/h.
Navien
The Navien NCB-210 is a first-generation wall-hung condensing combi from the discontinued NCB series: 18 to 100 MBH of heating input with 92 MBH heating capacity, 93.6% AFUE and DHW input to 180,000 BTU/h.
Twenty MBH of heating ceiling (100 against 80 MBH), 30,000 BTU/h more DHW input (180,000 against 150,000) and 0.6 GPM more flow at a 77°F rise, in the same cabinet at 84 versus 74 lb.
Yes. The NCB manual prints 2" or 3" PVC, CPVC or polypropylene venting (or special gas vent Type BH) for both, with forced-draft direct-vent installation.
Match the ceiling to the actual load: if the heat-loss calculation sits above the NCB-180's 80 MBH, the 210-class size is the safer basis. The current NCB-H line publishes higher AFUE and a different code set, so use its own literature for a new installation.
A consultation includes a heat-loss review so the size is right the first time.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.