Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The B1HE-85 and B1HE-120 are both 95% AFUE heating-only Vitodens 100-W models in the same 108 lb cabinet with identical dimensions, but their firing ranges differ: the 85 runs 8.5 to 85 MBH while the 120 runs 12 to 120 MBH. A heat-loss calculation decides which input ceiling the home needs, and the 85's lower minimum fire matches mild Lower Mainland loads more closely.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Viessmann Vitodens 100-W B1HE-85 | Viessmann Vitodens 100-W B1HE-120 |
|---|---|---|
| Input, minimum (natural gas) | 8.5 MBH | 12 MBH |
| Input, maximum (natural gas) | 85 MBH | 120 MBH |
| Efficiency (AFUE) | 95 % | 95 % |
| Weight | 108 lb | 108 lb |
| Domestic hot water | Not a combi; pair with an indirect tank | Not a combi; pair with an indirect tank |
Both are heating-only B1HE models on the same Vitodens 100-W platform, rated 95% AFUE with the MatriX-Plus burner and Inox-Radial stainless heat exchanger. The published difference is input range: 8.5 to 85 MBH (2.5 to 24.9 kW) for the 85, and 12 to 120 MBH (3.5 to 35.2 kW) for the 120.
The minimum fire rates matter more than they look: the 85 drops to 8.5 MBH and the 120 only to 12 MBH. In a tight, well-insulated home the 85 can match low shoulder-season demand without short-cycling, while the 120 idles at a higher floor; neither boiler produces domestic hot water, since both are heating-only with an indirect tank.
Weight and cabinet are identical — 108 lb (49 kg) and 17.75 x 19.75 x 33.75 inches (450 x 500 x 859 mm) — and the Canadian page quotes vent runs up to about 180 ft for the series. The choice therefore reduces to the room-by-room heat-loss calculation: if the load never approaches 85 MBH, the smaller model condenses more often in BC's mild climate.
Viessmann
The Vitodens 100-W B1HE-85 is the smallest boiler in Viessmann Canada's 100-W line: 8.5 to 85 MBH input at 95% AFUE in a 108 lb wall-hung cabinet, with the lowest minimum fire in the series for tight, well-insulated homes.
Viessmann
The Vitodens 100-W B1HE-120 is the mid-range heating-only model of Viessmann Canada's 100-W series: 12 to 120 MBH input, 95% AFUE, 108 lb, in the same compact cabinet as the B1HE-85.
Yes. Both weigh 108 lb (49 kg) and measure 17.75 x 19.75 x 33.75 inches (450 x 500 x 859 mm) per Viessmann Canada, so the installation footprint is identical.
When the heat-loss calculation plus indirect-tank recovery needs more than about 85 MBH. Extra input without a matching load only raises the minimum fire rate the boiler idles at in mild weather.
No. Both are heating-only; domestic hot water comes from an indirect tank paired with the boiler. The B1KE combi models in the same series provide on-demand DHW.
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 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.