Vaillant vs Viessmann - Which Heat Pump Is Better for UK Homes?
Independent head-to-head comparison. Updated April 2026.
Score breakdown
8.5
Efficiency (SCOP)
8.8
9
Reliability
8.9
8.5
Installation
7.8
8.5
After-sales support
8
7.8
Value for money
7.5
4
categories won by Vaillant
vs
1
categories won by Viessmann
Vaillant - installed price (post-grant)
£4,500 - £9,000
After £7,500 BUS grant. Includes installation.
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
V
Vaillant
Better value score (7.8/10) and typically lower installed cost
Long-term reliability
V
Vaillant
Higher reliability score (9/10)
Easiest installation
V
Vaillant
Better installer compatibility score (8.5/10)
After-sales support
V
Vaillant
Stronger UK support network (8.5/10)
V
Our verdict
Vaillant wins overall
Vaillant scores 8.8/10 overall - higher than Viessmann (8.7/10). However, the best choice depends on your specific priorities. Viessmann may be a better fit if you prioritise alternative criteria.
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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.