Navien NHB-55H
The Navien NHB-55H is the smallest NHB-H compact boiler: 8 to 55 MBH of input at 95.0% AFUE in a 17.3 x 12.8 x 23.8 in, 73 lb cabinet — built for low-load homes and tight mechanical rooms.
Key figures
- Max input
- 55 MBH
- Max CSA output
- —
- AFUE
- 95 %
- Min input
- 8 MBH
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Navien NHB-55H in practice
The NHB-55H modulates from 8,000 to 55,000 BTU/h of input, making it the smallest residential boiler Navien sells in Canada and a match for well-insulated homes, laneway houses and suites whose heat-loss calculation lands at the low end. Navien's quick facts list a 7:1 turndown for this model, and its 8 MBH minimum fire keeps it running steadily through mild shoulder seasons.
It is heating-only — domestic hot water comes from an indirect tank or a separate appliance — and its error table carries no DHW codes. At 17.3 x 12.8 x 23.8 in and 73 lb it fits spaces a full-size boiler cannot, and it vents in 2" or 3" PVC to 65 or 150 equivalent feet. The installation manual prints the model as NHB-055H.
Best suited to
- Well-insulated small homes, laneway houses and suites with low heat loss
- Mechanical rooms too tight for a full-height boiler cabinet
- Owners wanting the smallest condensing boiler that still carries Navien's 95.0% AFUE rating
Applicability and support
- Model number
- NHB-55H
- Canadian availability
- available
- Production status
- current
- ROMA supplies
- Confirmed at consultation
- ROMA services
- Confirmed at consultation
- Warranty
- Not verified
Where ROMA provides on-site service
On-site service is currently offered in Greater Vancouver, BC, including Vancouver, Burnaby, Richmond, Surrey, Coquitlam, North Vancouver, West Vancouver, New Westminster, Port Coquitlam, Port Moody, Delta, Langley, Maple Ridge, Abbotsford, Chilliwack, White Rock, Pitt Meadows, Tsawwassen, Anmore, Lions Bay, Belcarra, Bowen Island, Mission. Everything else on this site is reference information you can use anywhere in Canada.
Specifications
Published specifications
Values as published by Navien. Units are shown with every value; notes flag conflicting sources or missing figures.
| Specification | Value | Note |
|---|---|---|
| Input | ||
| Heating input, minimum | 8 MBH | Space-heating input. |
| Heating input, maximum | 55 MBH | Space-heating input. |
| Efficiency | ||
| Efficiency (AFUE) | 95 % | 95.0% AFUE per the installation manual. |
| Domestic hot water | ||
| Domestic hot water | Heating-only boiler; domestic hot water via an indirect tank or separate appliance | |
| Venting and air | ||
| Venting | PVC, CPVC or approved polypropylene; 2" or 3" | Canada: plastic venting must meet ULC S636 where required. |
| Max. equivalent vent length, 2" | 65 ft | |
| Max. equivalent vent length, 3" | 150 ft | |
| Physical and connections | ||
| Weight | 73 lb | 33 kg; per the installation manual. |
| Width | 17.3 in | |
| Height | 23.8 in | |
| Depth | 12.8 in | |
| Gas connection | 3/4" NPT | |
| Heating water connections | 1" NPT | |
| Operating limits and other | ||
| Fuel | Natural gas or propane | Separate Navien ratings per fuel. |
| Altitude rating | 10,100 ft | Per installation manual. |
| System water pressure | 12 – 30 psi | |
Manuals
Alerts documented for this model
Frequently asked questions
Is 55 MBH enough for my home?
That follows from a room-by-room heat-loss calculation. The NHB-55H caps at 55 MBH of input, so it suits homes whose calculated load fits comfortably below that; larger loads point to the NHB-80H or above.
Why does the manual call it NHB-055H?
The installation manual prints the model numbers with a leading zero (NHB-055H), while Navien's marketing pages and quick facts use NHB-55H. They are the same model.
Does the NHB-55H produce domestic hot water?
No. It is a heating-only boiler, so domestic hot water is handled by an indirect tank or a separate appliance.
Questions about the Navien NHB-55H?
Describe what the boiler is doing and get a straight answer about the next step.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
- Navien Canada — NHB-H series · accessed September 7, 2026
- NHB-H Installation and Operational Manual (EN) · accessed September 7, 2026
- NHB-H Service Manual, Ver 1.00 (July 2023) · Ver 1.00 · accessed September 7, 2026
Facts checked September 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.