Solar Savings Calculator UK
Fast, assumption-driven estimates for UK households.

Solar Savings Calculator (UK)

Adjust the assumptions below to estimate annual savings, export income and payback time.

Solar system cost (£)
System size (kW)
Annual generation (kWh)
Tip: many UK homes with ~4kW systems see roughly 2,800–4,000 kWh/year depending on location and shading.
Electricity unit rate (p/kWh)
Export rate (p/kWh)
Self-consumption (%)
How much solar you use in the home (daytime usage patterns matter a lot).
Include battery?
Battery cost (£)
Battery uplift to self-consumption (% points)
Simple model: battery increases how much solar you can use later. Adjust based on your expectations.
Annual savings
£530
60% self-consumed
Annual export income
£204
Based on export rate input
Annual total benefit
£734
Savings + export income
Payback time
15.0 years
Upfront cost: £11,000
10-year net gain
-£3,656
Benefit × 10 − upfront cost

Note: This is an estimate. Real results vary by roof orientation, shading, installer pricing, usage habits, and tariff changes.

How this UK solar savings calculator works

This tool estimates the financial impact of a solar PV system by splitting your annual generation into two parts: the electricity you use at home (self-consumption) and the electricity you export to the grid. Your self-consumed electricity is valued at your unit rate (p/kWh). Exported electricity is valued at your export rate (p/kWh).

If you enable the battery toggle, the calculator increases your effective self-consumption (based on the uplift you set) and adds the battery cost to the upfront total. The result is a simple, transparent comparison: higher self-use usually boosts annual savings, but the battery increases the upfront cost.

Because tariffs, usage patterns and installation quotes vary, this is designed to be assumption-driven. Adjust the inputs to reflect your situation and sanity-check multiple scenarios (conservative / expected / optimistic).

Quick tips to improve payback

  • Increase self-consumption: shift usage to daytime (washing, dishwashing, charging devices).
  • Get multiple installer quotes and compare like-for-like system sizes and warranties.
  • Use realistic annual generation estimates for your roof and location.
  • Test your unit rate and export rate sensitivity: payback can change materially.

FAQs

Do I need a battery for solar to be worth it in the UK?
Not necessarily. A battery can increase the percentage of solar you use at home, but it also increases upfront cost. Use the toggle to compare payback both ways using your own assumptions.
What inputs matter most?
Unit rate, self-consumption, and annual generation typically drive the result. Installation cost and export rate are also important, but self-consumption is often the biggest swing factor.
Is this calculator accurate?
It’s a directional estimate based on your inputs. Roof orientation, shading, household habits, installer pricing and tariff changes all affect outcomes in real life.
Does it include maintenance or replacements?
No. For a conservative view, increase upfront cost or reduce annual benefit slightly.