Sizing is a balance of electricity use, roof space, budget and whether you want to add battery storage. We start with your last 12 months of bills.
Rules of thumb by household
- Under 2,500 kWh/year: 3.0–3.5 kWp.
- 2,500 – 4,000 kWh/year: 4.0–5.0 kWp.
- 4,000 kWh+ or EV charging at home: 5.0–6.5 kWp.
Roof space
Modern panels (from 475W) take about 2m² each. Most UK homes have room for 10–14 panels on the main south, east or west aspect.
Battery storage
If you're out during the day, a battery moves solar generation into evening use and typically doubles the proportion of solar energy you actually consume yourself.