Solar Panels with Air Source Heat Pump

The synergy is simple: solar generates free electricity, and the heat pump multiplies that electricity into 3-4x more heat. Without solar, a heat pump saves money vs gas but you pay grid rates for the electricity. With solar, much of that electricity is free — dramatically improving the ROI of both systems.

Combined costs and savings: - Solar (5kW): £6,500-£9,500 - ASHP: £11,000 - £7,500 BUS grant = £3,500 - Total: £10,000-£13,000 - Annual savings vs gas + grid: £1,200-£2,000 - Payback: 5-9 years

Source: Energy Saving Trust; BUS grant; Ofgem Q1 2026.

A heat pump adds 3,000-4,000 kWh/year of electricity demand. You need a larger solar system to compensate:

• Home only: 4kW (10 panels)
• Home + heat pump: 6-8kW (15-20 panels)
• Home + heat pump + EV: 8-10kW (20-25 panels)

The larger system generates enough to cover most of the combined demand in spring/summer/autumn. Winter requires some grid import — but at off-peak rates (Octopus Go: 7.5p/kWh), the cost is minimal.

Source: PVGIS; heat pump consumption data.

The Boiler Upgrade Scheme provides £7,500 toward an ASHP installation. Combined with 0% VAT on solar:

• Solar (6kW): £8,000 at 0% VAT
• ASHP: £11,000 - £7,500 BUS = £3,500
• Combined: £11,500
• Annual savings: £1,200-£2,000
• Payback: 6-10 years

This is the most financially supported home energy combination available in the UK.

Source: BUS grant terms; Ofgem.