Head to head
Viessmann Vitocal 150-A10 vs Worcester Bosch Greenstar 2000 25kW combi
The Viessmann Vitocal 150-A10 is a r290 air source heat pump, 7.3 kw heat output. The Worcester Bosch Greenstar 2000 25kW combi is a gas combi boiler, 25 kw hot water output.
Last reviewed 13 September 2026
Specifications side by side
| Viessmann Vitocal 150-A10 | Worcester Bosch Greenstar 2000 25kW combi | |
|---|---|---|
| Dimensions | 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) | 724 x 400 x 300 mm |
| Weight | 162 kg (single fan) (outdoor unit) | 32.1 kg |
| Heat output | 7.3 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 | - |
| Hot water output | - | 25 kW |
| Central heating output | - | 3-24 kW |
| ErP class | - | A |
| Seasonal efficiency | - | 94% |
| Warranty | - | 7 years when installed with Greenstar System Filter |
| Hot water flow rate | - | 10 litres per minute at 35 C rise |
Sources: Viessmann Vitocal 150-A10, Worcester Bosch Greenstar 2000 25kW combi. Figures vary by model year and options, so check with the supplier before you commit.
Buy or hire the Vitocal 150-A10 if...
A Vitocal 150-A monobloc-style split heat pump using the natural refrigerant R290, rated at 7.3kW and reaching a 70C flow for boiler-replacement work. Viessmann-trained installers can extend the standard warranty on registration.
Full Vitocal 150-A10 specifications →Buy or hire the Greenstar 2000 25kW combi if...
A gas combi boiler with 25 kW of hot water output, sized for a flat or small house with one bathroom. It delivers about 10 litres per minute at 35 C rise of hot water, which decides how well a shower runs while a tap is on. Warranty: 7 years when installed with Greenstar System Filter. Seasonal efficiency is 94%.
Full Greenstar 2000 25kW combi specifications →Common questions
What is the difference between the Viessmann Vitocal 150-A10 and the Worcester Bosch Greenstar 2000 25kW combi?
The Viessmann Vitocal 150-A10 is a r290 air source heat pump, 7.3 kW heat output; the Worcester Bosch Greenstar 2000 25kW combi is a gas combi boiler, 25 kW hot water output.
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