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Baxi 800 Combi 2 36kW vs Vaillant ecoFIT pure 830 30kW combi

The Baxi 800 Combi 2 36kW runs 2.8 litres a minute more hot water and has 6kW more hot water output. The Vaillant ecoFIT pure 830 30kW combi is 1 points more efficient and puts out 0kW more to the radiators.

Last reviewed 13 September 2026

Key differences

Specifications side by side

Baxi 800 Combi 2 36kWVaillant ecoFIT pure 830 30kW combi
Hot water output36 kW30 kW
Central heating output26.4 kW26.5 kW
ErP classAA
Seasonal efficiency93%94%
Dimensions700 x 390 x 285 mm700 x 390 x 295 mm
Weight29.5 kg33 kg
Warranty10 years10 years when installed by Vaillant Advance installer
Hot water flow rate15 litres per minute12.2 litres per minute

Sources: Baxi 800 Combi 2 36kW, Vaillant ecoFIT pure 830 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 runs 2.8 litres a minute more hot water
  • you want one that has 6kW more hot water output

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 ecoFIT pure 830 30kW combi if...

  • you want one that is 1 points more efficient
  • you want one that puts out 0kW 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 when installed by Vaillant Advance installer. Seasonal efficiency is 94%.

Full ecoFIT pure 830 30kW combi specifications →

Common questions

What is the difference between the Baxi 800 Combi 2 36kW and the Vaillant ecoFIT pure 830 30kW combi?

The Baxi 800 Combi 2 36kW runs 2.8 litres a minute more hot water and has 6kW more hot water output. The Vaillant ecoFIT pure 830 30kW combi is 1 points more efficient and puts out 0kW more to the radiators. The Baxi 800 Combi 2 36kW is a gas combi boiler, 36 kW hot water output; the Vaillant ecoFIT pure 830 30kW combi is a gas combi boiler, 30 kW hot water output.

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