How many solar panels do I need?
Most UK homes need between 6 and 14 panels. The right number depends on how much electricity you use, where you live and how much roof you have.
Updated October 2026
Solar panels needed by household and region
| Household | Yearly use | South | Midlands | North | Scotland |
|---|---|---|---|---|---|
| Low (1 to 2 people, gas heating) | 1,800 kWh | 5 | 5 | 5 | 6 |
| Typical (3 people) | 2,700 kWh | 7 | 7 | 8 | 8 |
| High (4+ people) | 4,100 kWh | 10 | 11 | 11 | 12 |
| With an EV | 6,500 kWh | 15 | 17 | 18 | 19 |
| EV and heat pump | 9,000 kWh | 21 | 23 | 24 | 26 |
Panels needed to generate 100% of yearly use with 440 W panels on a south-facing roof with no shade. Usage figures for low, typical and high homes follow Ofgem's typical consumption values.
How to work it out yourself
- Find your yearly use. It's on your annual statement or energy app, in kWh. If you only know your bill, subtract the standing charge (about £200 a year) and divide by 26.32p.
- Find your area's output. Each kWp of panels makes about 800 kWh a year in Scotland and up to 1040 kWh in the South West.
- Divide. Yearly use ÷ output per kWp = system size in kWp. Divide by 0.44 for the number of 440 W panels.
Example: 2,700 kWh ÷ 920 kWh per kWp = 2.9 kWp, which is 7 panels in the Midlands.
Should you fit more panels than you need?
Often, yes. Panels are cheapest to add during the main installation, while the scaffolding is up. If you're likely to get an electric car or a heat pump within a few years, size for that now. An EV adds roughly 2,000 to 3,000 kWh a year and a heat pump 3,000 to 5,000 kWh.
Roof space usually sets the upper limit. A terraced house fits about 8 to 10 panels on one side, a semi 10 to 12 and a detached house 12 to 16. East and west roofs can take panels on both sides.
Frequently asked questions
How many solar panels do I need for a 3-bed house?
A typical 3-bed home uses about 2,700 kWh a year and needs 7 to 9 panels to cover it. Many owners fit 10 to 12 to cover rising use, an EV or a heat pump later.
How much roof space do solar panels need?
Each 440 W panel is about 1.7 m by 1.1 m, so needs roughly 2 m² including gaps. A 12-panel system needs around 24 m² of unshaded roof.
Can I have too many solar panels?
You can, if they cost more than the value of the power they make. Export payments are lower than the price you pay for electricity, so oversizing well beyond your use lengthens payback. A battery helps you use more of a larger system.
How much electricity does one solar panel produce?
A 440 W panel on a south-facing roof produces roughly 352 to 458 kWh a year in the UK, depending on where you live.
Get the exact number for your roof
The full calculator sizes the system to your roof and bill, then shows your savings.