Sizing Solar for a Heat Pump

How many solar panels do I need for a heat pump?

A typical UK air source heat pump (ASHP) uses 4,000-6,000 kWh of electricity per year to heat an average 3-bed home. To offset this with solar you need: 10-15 panels (4-6kW system). But timing matters — heat pumps run hardest in winter when solar output is lowest. Realistic solar offset: 30-40% of heat pump electricity directly, rising to 60-70% with a battery. Annual savings vs gas boiler: £600-£1,000/yr (solar + heat pump combined). Best setup: 6kW solar + 10kWh battery + ASHP. Total cost: £22,000-£27,000 (minus £7,500 BUS grant). Payback: 10-14 years.