Head to head
Mitsubishi Electric Ecodan PUZ-WM85VAA 8.5kW vs Worcester Bosch Greenstar 4000 25kW combi
The Mitsubishi Electric Ecodan PUZ-WM85VAA 8.5kW is a r32 monobloc air source heat pump, 8.5 kw heat output. The Worcester Bosch Greenstar 4000 25kW combi is a gas combi boiler, 25 kw hot water output.
Last reviewed 13 September 2026
Specifications side by side
| Mitsubishi Electric Ecodan PUZ-WM85VAA 8.5kW | Worcester Bosch Greenstar 4000 25kW combi | |
|---|---|---|
| Dimensions | 1020 x 1050 x 480 mm (H x W x D) | 710 x 400 x 310 mm |
| Weight | 98 kg | 32.0 kg |
| Heat output | 8.5 kW at A-7/W35 | - |
| ErP rating | 145% (MCS certified) | - |
| Refrigerant | R32, 2.2 kg charge | - |
| Sound power | 58 dBA | - |
| Sound pressure at 1m | 45 dBA | - |
| Max flow temperature | 55C (space heating) | - |
| Hot water output | - | 25 kW |
| Central heating output | - | 25 kW |
| ErP class | - | A |
| Seasonal efficiency | - | 94% |
| Warranty | - | 10 years |
| Hot water flow rate | - | 10.5 litres per minute |
Sources: Mitsubishi Electric Ecodan PUZ-WM85VAA 8.5kW, Worcester Bosch Greenstar 4000 25kW combi. Figures vary by model year and options, so check with the supplier before you commit.
Buy or hire the Ecodan PUZ-WM85VAA 8.5kW if...
An 8.5kW R32 monobloc heat pump, the middle unit in the Ecodan PUZ-WM line and a common size for a three-bed house. It runs on a single-phase 220-240V supply, weighs 98 kg and reaches a 55C flow temperature for radiator systems.
Full Ecodan PUZ-WM85VAA 8.5kW specifications →Buy or hire the Greenstar 4000 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 10.5 litres per minute of hot water, which decides how well a shower runs while a tap is on. Warranty: 10 years. Seasonal efficiency is 94%.
Full Greenstar 4000 25kW combi specifications →Common questions
What is the difference between the Mitsubishi Electric Ecodan PUZ-WM85VAA 8.5kW and the Worcester Bosch Greenstar 4000 25kW combi?
The Mitsubishi Electric Ecodan PUZ-WM85VAA 8.5kW is a r32 monobloc air source heat pump, 8.5 kW heat output; the Worcester Bosch Greenstar 4000 25kW combi is a gas combi boiler, 25 kW hot water output.
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