3kW or 4kW for a couple?

4kW — the extra cost (£500-£1,000) generates 25% more electricity. Even if you export the surplus now, you'll value the extra capacity when you add an EV, heat pump, or battery.

Do we need a battery?

If both work away: strongly recommended (boosts self-consumption from 30-40% to 70-85%). If one works from home: optional but still beneficial. A 5-8kWh battery costs £3,000-£4,500.

What about when we have children?

Electricity use increases with children (more laundry, lighting, heating). A 4kW system is already sized for this growth. You can add 2-4 panels later if needed.

Solar for Couples UK

By Home Solar Guide Team|Updated 18 March 2026|guide

Independently written | Evidence-based | Sources cited

Solar for couples — Couples: 3-4kW system, £5,000-£7,000, saves £480-£850/yr. The sweet spot.

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What size solar system for a couple?

Solar for couples: the most common UK solar installation scenario. CONSUMPTION: 2,500-3,500 kWh/yr. IDEAL SYSTEM: 3-4kW (8-10 panels). Cost: £5,000-£7,000 at 0% VAT. Generates: 2,700-3,800 kWh/yr — covering 80-110% of annual consumption. SAVINGS: £480-£850/yr without battery. £700-£1,100/yr with battery. Payback: 7-12 years. SELF-CONSUMPTION: If one person works from home: 50-65% (excellent). If both work away: 30-40% (battery recommended). FUTURE-PROOFING: if planning an EV or heat pump, consider installing 5-6kW now (£1,000-£1,500 extra) to avoid the cost of adding panels later.

Frequently Asked Questions

Related: Home Heating Systems

Solar panels are most powerful when combined with an efficient heating system. Heat pumps use solar-generated electricity to heat your home at 300-400% efficiency — making them the ideal partner for solar.

air source heat pump guide

Learn more about how air source heat pumps work alongside solar panels.

heat pump running costs in the UK

Heat pumps use electricity at 300-400% efficiency, making them ideal partners for solar.

heat pump installation process

Heat pump installation typically takes 2-3 days and is best planned alongside solar.

From our sister site Home Heat Pump Guide