Head to head
Baxi 800 Combi 2 36kW vs Viessmann Vitodens 100-W 30kW combi
The Baxi 800 Combi 2 36kW comes with 5 years more warranty and has 4kW more hot water output. The Viessmann Vitodens 100-W 30kW combi is 5 points more efficient.
Last reviewed 13 September 2026
Key differences
- Warranty: the Baxi 800 Combi 2 36kW comes with 5 years more warranty.
- Hot water output: the Baxi 800 Combi 2 36kW has 4kW more hot water output.
- Central heating output: the Baxi 800 Combi 2 36kW puts out 1kW more to the radiators.
- Seasonal efficiency: the Viessmann Vitodens 100-W 30kW combi is 5 points more efficient.
- Hot water flow rate: the Viessmann Vitodens 100-W 30kW combi runs 0.6 litres a minute more hot water.
Specifications side by side
| Baxi 800 Combi 2 36kW | Viessmann Vitodens 100-W 30kW combi | |
|---|---|---|
| Hot water output | 36 kW | 31.7 kW |
| Central heating output | 26.4 kW | 25 kW |
| ErP class | A | A |
| Seasonal efficiency | 93% | 98% |
| Dimensions | 700 x 390 x 285 mm | 700 x 400 x 360 mm |
| Weight | 29.5 kg | 35-38 kg |
| Warranty | 10 years | 5 years |
| Hot water flow rate | 15 litres per minute | 15.6 litres per minute |
Sources: Baxi 800 Combi 2 36kW, Viessmann Vitodens 100-W 30kW combi. Figures vary by model year and options, so check with the supplier before you commit.
Buy or hire the 800 Combi 2 36kW if...
- you want one that comes with 5 years more warranty
- you want one that has 4kW more hot water output
- you want one that puts out 1kW more to the radiators
A gas combi boiler with 36 kW of hot water output, sized for a larger house with two bathrooms. It delivers about 15 litres per minute of hot water, which decides how well a shower runs while a tap is on. Warranty: 10 years. Seasonal efficiency is 93%.
Full 800 Combi 2 36kW specifications →Buy or hire the Vitodens 100-W 30kW combi if...
- you want one that is 5 points more efficient
- you want one that runs 0.6 litres a minute more hot water
A gas combi boiler with 31.7 kW of hot water output, sized for a three-bed house with one or two bathrooms. It delivers about 15.6 litres per minute of hot water, which decides how well a shower runs while a tap is on. Warranty: 5 years. Seasonal efficiency is 98%.
Full Vitodens 100-W 30kW combi specifications →Common questions
What is the difference between the Baxi 800 Combi 2 36kW and the Viessmann Vitodens 100-W 30kW combi?
The Baxi 800 Combi 2 36kW comes with 5 years more warranty and has 4kW more hot water output. The Viessmann Vitodens 100-W 30kW combi is 5 points more efficient. The Baxi 800 Combi 2 36kW is a gas combi boiler, 36 kW hot water output; the Viessmann Vitodens 100-W 30kW combi is a gas combi boiler, 31.7 kW hot water output.
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