How Many Solar Panels Do I Need? (UK 2026)
Last updated 5 October 2026 · Prices based on the Ofgem price cap (October 2026 – December 2026)
The right number of panels depends on your annual electricity use, how much of it you want to generate, and how much suitable roof space you have.
How many solar panels do I need?
To cover 80% of 2,700 kWh you need about 2.4kWp — roughly 6 panels of 430W.
- System size
- 2.4 kWp
- Panels
- 6
- Roof area
- 12 m²
kWp = (annual use × share) ÷ yield per kWp. Each modern panel needs about 2 m² of roof.
Solar panels needed by household
| Household | Annual use | System size | Panels (430W) | Roof area |
|---|---|---|---|---|
| 1–2 people | 1,800 kWh | 2.2kWp | 5–6 | ≈12 m² |
| 3–4 people | 2,700 kWh | 3.5kWp | 8–9 | ≈18 m² |
| 5+ people | 4,100 kWh | 4.5kWp | 10–11 | ≈22 m² |
| With heat pump or EV | 6,000+ kWh | 6kWp+ | 14+ | ≈28 m² |
What affects the cost
Electricity use
Check your annual kWh on your bill.
Roof size
Allow for edges, vents and skylights.
Orientation
East-west roofs need more panels for the same output.
Future needs
An EV or heat pump will raise demand.
How to reduce the cost
- Plan for future EV or heat pump use
- Check with your DNO if over 3.68kW per phase (installer handles this)
- Higher-wattage panels save roof space
Frequently asked questions
How many solar panels does a 3-bed house need?
Usually 8–10 panels, giving 3.5–4.3kWp.
How much roof space do solar panels need?
About 2 m² per panel.
Can I have too many panels?
Systems over 3.68kW per phase need DNO approval, which your installer applies for.
Sources and methodology
Energy prices come from the Ofgem price cap for Direct Debit customers (GB average). Installation costs are typical UK ranges from installer quotes and industry guidance, rounded. Savings use today's rates and do not predict future prices.