How Much Can You Save? Solar ROI Explained

Saving money is the #1 reason Brits install solar. But relying on "average" figures can be misleading. Your savings depend on when you use electricity, not just how much you generate.

The Three Pillars of Savings

Your Return on Investment (ROI) comes from three sources:

Self-Consumption: Every unit (kWh) of solar power you use is a unit you don't buy from the grid. At current rates (~29p/kWh), this is the biggest saver.
Smart Export Guarantee (SEG): Energy companies must pay you for excess electricity sent back to the grid. Rates vary from 5p to 15p per kWh.
Battery Arbitrage: Charging your battery cheaply overnight (e.g., 7p/kWh on Octopus Intelligent) and using it during expensive peak hours.

Typical Payback Periods

"Payback period" = Total Cost / Annual Savings.

Best Case (South-facing, high usage, battery): 6 - 8 Years
Average Case (Semi-detached, family usage): 8 - 12 Years
Poor Case (Shaded roof, low usage, no export tariff): 15+ Years

Real World Example: The "Smith" Family

Scenario: 4kW System in Leeds

Cost: £7,000 (no battery)
Generation: 3,400 kWh / year
Usage: Family home during the day (50% self-consumption)

Savings (1,700 kWh @ 29p): £493 / year
Export Income (1,700 kWh @ 15p): £255 / year
Total Annual Benefit: £748
Payback: 9.3 Years

Impact of Energy Price Cap

Solar is a hedge against inflation. If energy prices rise, your savings increase proportionally. Even if prices fall, the hardware costs have already been paid, securing your energy rate at roughly 5p-6p/kWh (the lifetime cost of the system) for the next 25 years.

Want to calculate your specific scenario? Try our Interactive Calculator.