Grant UK vs Viessmann - Which Heat Pump Is Better for UK Homes?
Independent head-to-head comparison. Updated April 2026.
Score breakdown
8
Efficiency (SCOP)
8.8
8.2
Reliability
8.9
9
Installation
7.8
9.2
After-sales support
8
8.5
Value for money
7.5
3
categories won by Grant UK
vs
2
categories won by Viessmann
Grant UK - installed price (post-grant)
£3,800 - £8,000
After £7,500 BUS grant. Best UK support network.
BUS Grant: £7,500Viessmann - installed price (post-grant)
£5,000 - £10,000
After £7,500 BUS grant. Premium German specification.
BUS Grant: £7,500Which wins for...
Maximum efficiency
Vi
Viessmann
Higher SCOP rating (8.8/10)
Best value for money
G
Grant UK
Better value score (8.5/10) and typically lower installed cost
Long-term reliability
Vi
Viessmann
Higher reliability score (8.9/10)
Easiest installation
G
Grant UK
Better installer compatibility score (9/10)
After-sales support
G
Grant UK
Stronger UK support network (9.2/10)
Vi
Our verdict
Viessmann wins overall
Viessmann scores 8.7/10 overall - higher than Grant UK (8/10). However, the best choice depends on your specific priorities. Grant UK may be a better fit if you prioritise value for money.
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Important disclaimer
www.heatpumpcompared.co.uk is editorially independent and not affiliated with any heat pump manufacturer or installer. We do not provide heating advice. Prices, specifications, SCOP ratings and grant amounts are correct as of April 2026 but are subject to change. Always commission a professional heat loss survey before purchasing a heat pump system.