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Solar panel payback in London
How fast does a 4 kWp domestic solar system pay back in London, what does it save in year 1, and what's the 25-year net benefit? This page uses the same assumptions as our full solar calculator — only the local irradiance (PVGIS annual yield for the SW1A outcode) changes.
What makes London different
The capital sits in one of the UK's sunnier corridors — solar yield here is within 5% of Bristol and Southampton.
The figures above use a 4 kWp south-facing system, no battery, 3,500 kWh/yr household use, 27p/kWh import tariff, 15p/kWh SEG export and 4%/yr electricity inflation — the same defaults as the full UK solar calculator. Yield here (975 kWh/kWp) is drawn from PVGIS satellite data for the SW1A outcode. If you want to model a battery, a larger system, east/west panels or a different tariff, open the main solar calculator — it accepts your exact postcode and full custom inputs.
Model it for your exact postcode
The numbers above assume the outcode SW1A. For your postcode — which adjusts irradiance slightly — use the calculator below.
Compare other cities
Pick any UK city to see its solar payback side-by-side with London.
Getting accurate quotes in London
The calculator gives a tight estimate, but three local factors decide your real payback: roof orientation (south ≥ east/west by 15–20%), shading from chimneys, trees and neighbours, and installer pricing — which varies wildly even within a single city. Get at least three MCS-certified quotes before committing.
If you're also looking at batteries, check which UK Smart Export Guarantee tariff will pay you the most — it changes the whole payback equation. And if you're considering a heat pump alongside solar, start with the heat pump vs gas boiler calculator and the £7,500 BUS grant check.