Solar Panel Savings Calculator UK

Calculate your solar panel investment returns, payback period, and long-term savings with Smart Export Guarantee (SEG) rates.

System Details

Typical UK home: 3-5kW
Average: £5,000-£7,000
South-facing is most efficient
UK average: 2,700-4,000 kWh

Electricity Rates

Jul-Sep 2026 price cap: 26.11p
UK average SEG: 4.1p

Quick Tips

  • Optimal orientation: South-facing roofs generate the most electricity
  • System size: Typical UK homes install 3-5kW systems
  • SEG rates: Compare suppliers - rates vary from 3p to 15p/kWh
  • Battery storage: Can increase self-consumption from ~40% to ~70%
  • Grants: Check for local authority solar grants

Roof Orientation Impact

Direction Efficiency
South 100%
SW/SE ~90%
East/West ~80%
North ~60%

Frequently Asked Questions

What is the average payback period for solar panels in the UK?

The typical payback period for solar panels in the UK is 8-12 years, depending on system size, installation cost, electricity rates, and roof orientation. South-facing roofs generally achieve faster payback times.


What is the Smart Export Guarantee (SEG)?

The Smart Export Guarantee (SEG) is a UK government scheme requiring energy suppliers to pay households for excess solar electricity exported to the grid. SEG rates typically range from 3p to 15p per kWh, with an average around 4.1p/kWh.


How much do solar panels cost in the UK?

A typical 4kW residential solar panel system costs between £4,000 and £8,000 installed in the UK. Prices have decreased significantly in recent years, making solar more accessible for homeowners.


How much electricity does a 4kW solar system generate in the UK?

A 4kW south-facing solar system in the UK typically generates around 4,200 kWh per year. Generation varies based on location, roof orientation, shading, and weather conditions.


Does roof orientation affect solar panel performance?

Yes, significantly. South-facing roofs are optimal in the UK, generating around 1050 kWh per kW installed. Southwest or southeast roofs produce about 90% of south-facing output, while east or west-facing roofs produce around 80%, and north-facing roofs only about 60%.

Disclaimer: This calculator provides estimates for illustrative purposes only and should not be considered financial advice. Actual solar panel performance and savings depend on many factors including location, weather, shading, system quality, and maintenance. Consult with MCS-certified solar installers for accurate quotes and projections. SEG rates and electricity prices vary by supplier and may change. Last updated: August 2026.