Thinking about solar panels for your home? This calculator is designed for a typical 3-bed semi-detached house in Southampton with a south-facing roof. Based on your roof size of 30m² and an annual electricity bill of £1,200, we've estimated the potential savings, payback period, and environmental benefits. Use these figures to see if solar could be a smart investment for you.
Your Solar Savings Calculator Results
Based on your inputs, here’s what a solar panel system could do for your Southampton home. The table below shows the key numbers — all estimates based on typical UK conditions.
| Metric | Value |
|---|---|
| System size | 5.4 kWp |
| Annual generation | 5,670 kWh |
| Annual savings | £794 |
| Bill reduction | 46% |
| Install cost | £5,940 |
| Payback period | 7.5 years |
| CO₂ saved | 1.3 tonnes/yr |
| Export income | £238/yr |
A 5.4 kWp system on your 30m² roof could generate 5,670 kWh per year, saving you approximately £794 annually. The system would pay for itself in around 7.5 years.
How We Calculated Your Savings
We used standard solar panel performance data for a south-facing roof in southern England. Your 30m² roof can fit about 15 panels (at 360W each), giving a total system size of 5.4 kWp. Annual generation of 5,670 kWh is based on UK solar radiation figures from the Energy Saving Trust. We assumed you use 50% of the generated electricity in your home, saving you the retail price per kWh, and export the rest at the Smart Export Guarantee rate of 15p per kWh. The install cost of £5,940 is typical for a system of this size, and the payback period is the install cost divided by annual savings plus export income.
Savings Breakdown
Your annual bill of £1,200 is reduced by £794 — that’s a 46% cut. You also earn £238 per year from exporting surplus electricity. Over 25 years, total savings could exceed £25,000, making solar a solid investment.
Why Solar Works for Your Home
Southampton gets good sunlight, and a south-facing roof is ideal. With a 5.4 kWp system, you’ll generate more than enough to cover daytime usage. The Smart Export Guarantee pays you for any excess electricity you send back to the grid. Over the system’s lifetime, you’ll save money and cut your carbon footprint.
Next Steps
Ready to get solar panels? Check if you’re eligible for the Boiler Upgrade Scheme for heat pump grants, which can complement solar. For more advice on solar panels, visit the Energy Saving Trust. Always use an MCS-certified installer — find one at MCS Certified.
How these numbers were calculated
We used standard solar irradiance data for southern England and a south-facing roof to estimate generation. System size is based on fitting 360W panels on a 30m² roof. Savings assume 50% self-consumption of generated electricity, with the rest exported at the Smart Export Guarantee rate of 15p/kWh. Install cost is an average UK price of £1,100 per kWp. Payback is calculated by dividing total cost by annual savings plus export income.
Sources
- Energy Saving Trust — Solar panels
- Ofgem — Smart Export Guarantee
- MCS Certified — Find an installer
