Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The NCB-150E and NCB-180E are the two smallest NCB-E combis and both print 95.0% AFUE. The 180E adds 20 MBH of heating ceiling (80 against 60), raises DHW input from 120,000 to 150,000 BTU/h and flow from 2.6 to 3.4 GPM at a 77°F rise, and weighs 74 lb against the 150E's 66 lb in the same 17 x 28 x 12 in cabinet.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Navien NCB-150E | Navien NCB-180E |
|---|---|---|
| Heating input, minimum | 12 MBH | 14 MBH |
| Heating input, maximum | 60 MBH | 80 MBH |
| Heating capacity | 56 MBH | 75 MBH |
| Net AHRI water rating | 49 MBH | 65 MBH |
| Efficiency (AFUE) | 95 % | 95 % |
| DHW input, maximum | 120 MBH | 150 MBH |
| DHW flow rate at 77°F (43°C) rise | 2.6 GPM | 3.4 GPM |
| Weight | 66 lb | 74 lb |
The NCB-150E and NCB-180E open the NCB-E line, the generation between the original NCB and today's NCB-H. The specification sheet prints a 12 to 60 MBH heating range for the 150E with a 56 MBH capacity and a 49 MBH net AHRI water rating; the 180E fires 14 to 80 MBH with a 75 MBH capacity and a 65 MBH net rating. Both are 95.0% AFUE.
The DHW step is significant at this end of the line: 120,000 against 150,000 BTU/h of DHW input and 2.6 against 3.4 GPM at a 77°F (43°C) rise. The 150E's lower flow suits one-bathroom demand patterns; the 180E's larger DHW side is the reason most small-home combi replacements start at the 180 size.
Both share the same cabinet dimensions, 1" NPT heating connections, 3/4" NPT DHW and gas connections, 0.5 GPM minimum DHW flow and 2"/3" venting options; the 180E is 8 lb heavier (74 against 66 lb). Because the series is discontinued, owners should also match the NCB-E generation's own service manual when diagnosing either unit.
Navien
The Navien NCB-150E is a previous-generation wall-hung condensing combi from the discontinued NCB-E series: 12 to 60 MBH heating input, 56 MBH capacity at 95.0% AFUE, and DHW input to 120,000 BTU/h.
Navien
The Navien NCB-180E is a previous-generation wall-hung condensing combi from the discontinued NCB-E series: 14 to 80 MBH heating input, 75 MBH capacity at 95.0% AFUE, and DHW input to 150,000 BTU/h.
No. Both print 95.0% AFUE on the NCB-E specification sheet; the differences are the heating and DHW ceilings, flow and weight.
The 150E covers a 60 MBH heating ceiling and 120,000 BTU/h DHW input; the 180E steps to 80 MBH and 150,000 BTU/h. The heat-loss calculation and hot-water demand decide, not the house's floor area.
They share the same wall-hung chassis dimensions and connection sizes, but always confirm part numbers against the specific model's parts list — the NCB-E generation differs from both the original NCB and the current NCB-H.
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.