Head to head
Baxi 800 Combi 2 36kW vs Viessmann Vitocal 150-A13
The Baxi 800 Combi 2 36kW is a gas combi boiler, 36 kw hot water output. The Viessmann Vitocal 150-A13 is a r290 air source heat pump, 8.1 kw heat output.
Last reviewed 13 September 2026
Specifications side by side
| Baxi 800 Combi 2 36kW | Viessmann Vitocal 150-A13 | |
|---|---|---|
| Dimensions | 700 x 390 x 285 mm | 920 x 450 x 360 mm (H x W x D) (indoor unit); 841 x 1144 x 600 mm (H x W x D, single fan) (outdoor unit) |
| Weight | 29.5 kg | 162 kg (single fan) (outdoor unit) |
| Hot water output | 36 kW | - |
| Central heating output | 26.4 kW | - |
| ErP class | A | - |
| Seasonal efficiency | 93% | - |
| Warranty | 10 years | - |
| Hot water flow rate | 15 litres per minute | - |
| Heat output | - | 8.1 kW at A7/W35 |
| COP | - | 4.7-5.0 at A7/W35 |
| Refrigerant | - | R290 (propane), GWP 0.02 |
| Sound power | - | 51 dB(A) assessed total at A7/W55 |
| Max flow temperature | - | 70C down to -10C outdoor |
Sources: Baxi 800 Combi 2 36kW, Viessmann Vitocal 150-A13. Figures vary by model year and options, so check with the supplier before you commit.
Buy or hire the 800 Combi 2 36kW if...
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 Vitocal 150-A13 if...
A Vitocal 150-A monobloc-style split heat pump using the natural refrigerant R290, rated at 8.1kW and reaching a 70C flow for boiler-replacement work. Viessmann-trained installers can extend the standard warranty on registration.
Full Vitocal 150-A13 specifications →Common questions
What is the difference between the Baxi 800 Combi 2 36kW and the Viessmann Vitocal 150-A13?
The Baxi 800 Combi 2 36kW is a gas combi boiler, 36 kW hot water output; the Viessmann Vitocal 150-A13 is a r290 air source heat pump, 8.1 kW heat output.
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