How did you calculate savings by postcode?

We used PVGIS to determine annual solar irradiance (kWh/m²/yr) for the geographic centre of each postcode district. We then applied a standard 4kW system at 20% panel efficiency, 35-50% self-consumption rate, Ofgem Q1 2026 unit rate (24.5p/kWh), and regional average SEG export rate. Full methodology published on our methodology page.

Why does Portsmouth save more than Aberdeen?

Portsmouth receives approximately 1,080 kWh/m²/yr of solar irradiance vs Aberdeen's 880 kWh/m²/yr — a 23% difference. When combined with slightly higher self-consumption rates in southern England and marginally higher regional electricity costs, the savings gap widens to 30-40%.

Is this data reliable?

Yes — PVGIS is the European Commission's official solar radiation database, used by the solar industry worldwide. Ofgem publishes official electricity price caps quarterly. ONS provides the UK's official energy consumption statistics. Our methodology combines these three authoritative sources.

What assumptions did you use?

Standard 4kW system (10 × 400W panels), 30-35° roof tilt, south-facing orientation, 40% self-consumption without battery (65% with battery), 0.5% annual degradation, Ofgem Q1 2026 cap rate of 24.5p/kWh, and average SEG export rate of 5.5p/kWh.

Can I get data for my specific postcode?

The analysis covers all 124 postcode areas and 2,900+ postcode districts in the UK. Use our Solar Panel Calculator for a personalised estimate that includes your roof orientation and electricity usage.

Solar Savings by Postcode: The UK Map

By Home Solar Guide Team|Updated 19 March 2026|guide

Independently written | Evidence-based | Sources cited

Solar savings by UK postcode map — First-ever postcode-level solar savings analysis — combining PVGIS, Ofgem, and ONS data.

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How much do solar panels save in my postcode?

We analysed solar savings for every UK postcode district by combining three authoritative datasets: PVGIS solar irradiance data (European Commission Joint Research Centre), Ofgem electricity price cap rates, and ONS household consumption statistics. Results: Annual savings range from £520 in Lerwick (ZE1) to £1,180 in Portsmouth (PO1) for a standard 4kW system. The UK average is £780/yr. Southern England postcodes save 25-35% more than Scottish postcodes — but even the lowest-saving postcodes deliver positive ROI within 14 years. Key finding: the gap between best and worst UK postcodes is only 56% — far smaller than most people assume. Solar works everywhere in the UK. Sources: PVGIS (re.jrc.ec.europa.eu), Ofgem price cap Q1 2026 (ofgem.gov.uk), ONS Energy Consumption in the UK 2025 (ons.gov.uk).

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