Find the solar size that fits your bill
Enter your average monthly units or bill to estimate a system that matches your annual usage. You will see the likely panel count, roof area and subsidy band before you speak to an installer.
kWh
Add up 12 bills and divide by 12; summer alone overstates it.
Recommended size
2.5 kW
- Consumption used
- 300 units a month
- Expected generation
- about 281 units a month
- Panels
- 5 × 540 Wp
- Roof needed
- 250–292 sq ft, shadow-free
- Subsidy note
- within the subsidised 3 kW band
Sizing matches annual consumption to annual generation at 113 units per kW per month (the published planning yield with a 10% derate). Your sanctioned load and roof shading decide the final size; an engineer confirms both on a free visit. Prices for this size: see the 3 kW page.