Head to head
Baxi 800 Combi 2 30kW vs Vaillant ecoFIT pure 825 25kW combi
The Baxi 800 Combi 2 30kW has 5kW more hot water output and runs 1.8 litres a minute more hot water. The Vaillant ecoFIT pure 825 25kW combi is 1 points more efficient.
Last reviewed 13 September 2026
Key differences
- Hot water output: the Baxi 800 Combi 2 30kW has 5kW more hot water output.
- Hot water flow rate: the Baxi 800 Combi 2 30kW runs 1.8 litres a minute more hot water.
- Central heating output: the Baxi 800 Combi 2 30kW puts out 2kW more to the radiators.
- Seasonal efficiency: the Vaillant ecoFIT pure 825 25kW combi is 1 points more efficient.
Specifications side by side
| Baxi 800 Combi 2 30kW | Vaillant ecoFIT pure 825 25kW combi | |
|---|---|---|
| Hot water output | 30 kW | 25.2 kW |
| Central heating output | 21.2 kW | 19.1 kW |
| ErP class | A | A |
| Seasonal efficiency | 93% | 94% |
| Dimensions | 700 x 390 x 285 mm | 700 x 390 x 295 mm |
| Warranty | 10 years | 10 years when installed by Vaillant Advance installer |
| Hot water flow rate | 12.2 litres per minute | 10.4 litres per minute |
| Weight | - | 32 kg |
Sources: Baxi 800 Combi 2 30kW, Vaillant ecoFIT pure 825 25kW combi. Figures vary by model year and options, so check with the supplier before you commit.
Buy or hire the 800 Combi 2 30kW if...
- you want one that has 5kW more hot water output
- you want one that runs 1.8 litres a minute more hot water
- you want one that puts out 2kW more to the radiators
A gas combi boiler with 30 kW of hot water output, sized for a three-bed house with one or two bathrooms. It delivers about 12.2 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 30kW specifications →Buy or hire the ecoFIT pure 825 25kW combi if...
- you want one that is 1 points more efficient
A gas combi boiler with 25.2 kW of hot water output, sized for a flat or small house with one bathroom. It delivers about 10.4 litres per minute of hot water, which decides how well a shower runs while a tap is on. Warranty: 10 years when installed by Vaillant Advance installer. Seasonal efficiency is 94%.
Full ecoFIT pure 825 25kW combi specifications →Common questions
What is the difference between the Baxi 800 Combi 2 30kW and the Vaillant ecoFIT pure 825 25kW combi?
The Baxi 800 Combi 2 30kW has 5kW more hot water output and runs 1.8 litres a minute more hot water. The Vaillant ecoFIT pure 825 25kW combi is 1 points more efficient. The Baxi 800 Combi 2 30kW is a gas combi boiler, 30 kW hot water output; the Vaillant ecoFIT pure 825 25kW combi is a gas combi boiler, 25.2 kW hot water output.
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