Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The Navien NCB-180 and Navien NCB-240 are both combination (combi) boilers in the Navien NCB (first generation) line. Published ratings: Navien NCB-180 at 14–80 MBH input, 74 MBH heating capacity and 93.5% AFUE; Navien NCB-240 at 18–120 MBH input, 109 MBH heating capacity and 93.3% AFUE. Navien NCB-240 lists 40 MBH more input than Navien NCB-180 (120 MBH against 80 MBH). Navien NCB-180 carries the higher published AFUE at 93.5%, against 93.3%. Navien NCB-240 lists 10 lb more shipping weight than Navien NCB-180 (84 lb against 74 lb).
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Navien NCB-180 | Navien NCB-240 |
|---|---|---|
| Heating input, minimum | 14 MBH | 18 MBH |
| Heating input, maximum | 80 MBH | 120 MBH |
| Heating capacity | 74 MBH | 109 MBH |
| Efficiency (AFUE) | 93.5 % | 93.3 % |
| DHW input, minimum | 14 MBH | 18 MBH |
| DHW input, maximum | 150 MBH | 199.9 MBH |
| Weight | 74 lb | 84 lb |
| Height | 28 in | 28 in |
| Width | 17 in | 17 in |
| Depth | 12 in | 12 in |
| Venting | 2" or 3" PVC, CPVC, polypropylene; 2" or 3" special gas vent Type BH (Class III A/B/C) | 2" or 3" PVC, CPVC, polypropylene; 2" or 3" special gas vent Type BH (Class III A/B/C) |
| Heating connections | 1" NPT | 1" NPT |
| Gas connection | 3/4" NPT | 3/4" NPT |
| Fuel | Natural gas or propane | Natural gas or propane |
| Net AHRI water rating | 64 MBH | 95 MBH |
| DHW flow rate at 77°F (43°C) rise | 3.4 GPM | 4.5 GPM |
| Hydronic water pressure | 12 – 30 psi | 12 – 30 psi |
| DHW connections | 3/4" NPT | 3/4" NPT |
Published ratings: the Navien NCB-180 is rated 14–80 MBH input, 74 MBH heating capacity and 93.5% AFUE; the Navien NCB-240 is rated 18–120 MBH input, 109 MBH heating capacity and 93.3% AFUE. Navien NCB-240 lists 40 MBH more input than Navien NCB-180 (120 MBH against 80 MBH). Navien NCB-180 carries the higher published AFUE at 93.5%, against 93.3%.
Navien NCB-240 lists 10 lb more shipping weight than Navien NCB-180 (84 lb against 74 lb). The domestic-hot-water input differs: the Navien NCB-180 lists 14 MBH, while the Navien NCB-240 lists 18 MBH. The domestic-hot-water input differs: the Navien NCB-180 lists 150 MBH, while the Navien NCB-240 lists 199.9 MBH. The dhw flow rate at 77°F rise differs: the Navien NCB-180 lists 3.4 GPM, while the Navien NCB-240 lists 4.5 GPM.
Both records print the same height (28 in), width (17 in), depth (12 in) and venting (2" or 3" PVC, CPVC, polypropylene; 2" or 3" special gas vent Type BH (Class III A/B/C)), per the cited sources.
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-240 is a first-generation wall-hung condensing combi from the discontinued NCB series: 18 to 120 MBH of heating input with 109 MBH heating capacity, 93.3% AFUE and DHW input to 199,900 BTU/h.
The Navien NCB-240 lists 120 MBH, against 80 MBH on the Navien NCB-180, per the cited documentation.
The Navien NCB-180 carries the higher published AFUE at 93.5%, against 93.3%.
It ships at 84 lb against 74 lb for the Navien NCB-180, per the cited sources.
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.