Solar Panel Savings by Postcode: How Location Affects Your Return

Plug-in solar economics boil down to one unavoidable fact: where you are in the UK determines how much sun you get, and that determines how much you save.

A 400W system in Cornwall generates ~15% more electricity than the same system in Newcastle. The cost is identical, but the return is notably different. This article maps out real regional variation—so you can see whether your postcode favours solar or makes it a tighter financial call.

The Geography of UK Solar Generation

The UK's solar potential follows a clear south-to-north gradient, driven by:

1. Latitude – Southern sites have a higher sun angle, especially in winter.
2. Cloud cover – Northern and Western regions are cloudier on average.
3. Altitude – Highland areas and moorland are windier but cloudier.
4. Urban vs rural – Some cities have worse air quality (smog reduces irradiance slightly).

The European Commission's PVGIS database holds 30 years of satellite irradiance data, updated annually. Using this, we can forecast generation for any postcode to within ±3–5% accuracy.

Regional Breakdown: Generation by System Size

These figures are for 800W south-facing systems, tilted at 25°, with no shading. They represent typical annual generation and estimated annual savings at 30p/kWh.

South-East England (London, Reading, Brighton)

Solar Irradiance: ~1,050 kWh/m²/year (highest in UK)

London is the benchmark. Clear skies, reasonable latitude, and low cloud cover. Any system installed in Greater London or the Home Counties will hit these figures or exceed them.

Postcodes: SW, SE, M25, KT, CR, BR, EN, CM

South-West England (Bristol, Exeter, Penzance)

Solar Irradiance: ~980 kWh/m²/year

The South-West is nearly as sunny as London. Penzance and coastal areas benefit from ocean reflection. Inland rural areas (Dartmoor, Exmoor) are slightly cloudier but still excellent.

Postcodes: BS, EX, PL, TR, TA, DT, BH

Midlands & Central (Birmingham, Nottingham, Coventry)

Solar Irradiance: ~950 kWh/m²/year

The Midlands are a transition zone between the sunny South and the cloudier North. Generation is solid, with a payback just slightly longer than London.

Postcodes: CV, WV, DY, B, WS, DE, ST, LE

South Wales & Valleys

Solar Irradiance: ~920 kWh/m²/year

South Wales coastal areas (Cardiff, Swansea) are sunnier than inland valleys (Merthyr, Ebbw Vale). Cloud cover from Atlantic systems is the limiting factor.

Postcodes: CF, SA

North-West England (Manchester, Liverpool, Chester)

Solar Irradiance: ~920 kWh/m²/year

The North-West suffers from Atlantic cloud cover, but lower latitude than Scotland. Manchester and Liverpool are marginally less sunny than the Midlands, but still very much viable for solar.

Postcodes: M, L, WA, CW, CH, PR, BB, BN

Yorkshire & North-East (Leeds, York, Newcastle)

Solar Irradiance: ~900 kWh/m²/year

The North is noticeably cloudier. Leeds and York are marginally better than Newcastle, but all three regions are within the 3.5–3.6 year payback bracket.

Postcodes: LS, YO, HG, DL, SR, NE, TS

East Anglia & East Midlands (Norwich, Peterborough, Lincoln)

Solar Irradiance: ~1,000 kWh/m²/year (second-best in UK)

East Anglia is a hidden solar gem. Low altitude, relatively low cloud cover, and good sun exposure—almost on par with the South-East. Norfolk and Suffolk often outperform expectations.

Postcodes: NR, PE, NE, LN, NG, NN, MK

Scotland (Edinburgh, Glasgow, Aberdeen)

Solar Irradiance: ~800 kWh/m²/year (lowest in UK)

Scotland's challenge: low latitude and high latitude days compensate for longer summer days, but cloud cover is the real brake. Edinburgh payback is under 4 years, which is still respectable, but generation is ~20% lower than London.

Postcodes: EH, G, KA, DG, FK

Northern Ireland (Belfast)

Solar Irradiance: ~820 kWh/m²/year

Belfast is marginally better than mainland Scotland, benefiting from coastal reflectance and marginally lower cloud cover.

Postcodes: BT

Welsh Uplands & Rural Wales (Aberystwyth, Bangor, Snowdonia)

Solar Irradiance: ~850 kWh/m²/year (higher altitude = clearer air, but more wind/cloud)

Rural Wales is cloudier than South Wales, and higher altitude means more wind (and less sunshine in winter). Still viable, but payback is tighter than the South.

Postcodes: LL, SY, HR, LD, NP

Quick Postcode Lookup: What's Your Solar Potential?

Your postcode area's first 1–2 letters roughly predict solar potential:

• BN, EH, CR, EN, M25, KT, BR, SW, SE, CT – Excellent (1,000+ kWh/m²/yr) – 3.1–3.2 year payback
• BS, EX, PL, TR, NR, PE, NG – Very Good (950–1,000 kWh/m²/yr) – 3.2–3.4 year payback
• CV, WV, WS, DE, ST, LE, NN – Good (900–950 kWh/m²/yr) – 3.4–3.5 year payback
• CF, SA, M, L, WA, CW, CH, PR, DL, SR, NE, TS – Good (850–920 kWh/m²/yr) – 3.5–3.7 year payback
• LS, YO, HG, DT, BH, HR, LD – Fair (800–900 kWh/m²/yr) – 3.7–3.9 year payback
• EH, G, KA, DG, FK, LL, SY, NP, BT – Fair to Limited (750–850 kWh/m²/yr) – 3.8–4.2 year payback

Bottom line: Even in Scotland, payback is under 4 years. Even in the sunniest South, it's above 3 years. Regional variation is real but not dramatic—the entire UK is within the "worth doing" zone.

How Shading Crushes Regional Advantage

Here's the catch: postcode potential can be completely overridden by shading.

A north-facing wall in sunny London generates less than an unshaded south-facing balcony in cloudy Manchester.

This is why the Solar Report tool matters more than postcode. It looks at your specific property, your exact aspect, and shade patterns from nearby buildings and trees. You might be in an "excellent" postcode but have chimneys and trees that cut generation by 30%.

Shading impact examples:

• Winter shade from a single tree: -10 to 20% generation
• Chimney or building casting a shadow: -15 to 40% generation (depending on time of year and panel orientation)
• Flat-roof panels shadowed by a slightly taller building: -30 to 50%

Always check the Solar Report for your specific property; don't rely on postcode alone.

Tariff Variation Beats Postcode Variation

Here's something reassuring: switching to a better electricity tariff can gain you 20–50% more savings than moving to a sunnier postcode.

A London user on standard 30p/kWh saves £256/year with 800W. A London user on Octopus Flux (15p peak, export rewards) saves ~£300–£350/year with the same system. That's the equivalent of moving from London's sunny climate to a 50% sunnier hypothetical place—just by choosing a smarter tariff.

See the tariff guide for details.

Using the Calculator for Your Exact Postcode

These regional figures are averages and can vary by 1–2% depending on exactly where you are in a postcode area. For precision, run the calculator:

1. Enter your full postcode (e.g., SW1A 1AA, not just SW).
2. Specify your aspect (south, SE/SW, east/west).
3. Choose your system size (400W, 600W, 800W).
4. Add your tariff (standard or custom rate).

The calculator queries PVGIS with your exact coordinates and gives a personalised estimate.

Inter-Regional Comparisons

Moving 100 km south gains you ~3–5% generation. Moving 100 km north costs you 3–5%. This compounds over latitude:

• London to Birmingham: ~80 km, -2.5% generation
• London to Manchester: ~300 km, -7% generation
• London to Edinburgh: ~650 km, -20% generation

But, a south-facing 800W system anywhere in the UK beats a north-facing 400W system in the sunniest location.

Aspect and shading dominate postcode for a single property. But if you're comparing two properties in different regions, region matters.

Future: Will Climate Change Shift This?

Solar generation is improving slightly year-on-year in the UK as air quality improves (less smog = more direct sunlight). Some models suggest the UK may see +0.5% generation per decade as the Atlantic warms and high-pressure systems become more frequent.

This is a bonus, not a core assumption. Conservative estimates use historical 20-year PVGIS data, which is the right approach.

Key Takeaways

• Regional variation is 20–30% – sunny south saves 20–30% more than cloudy north, but payback is still 3–4 years everywhere.
• Postcode is the second lever – your aspect and shading are more important than region for a single property.
• East Anglia is a hidden gem – nearly as sunny as the South-East, often overlooked.
• Scotland is still worth it – under 4-year payback, even in Edinburgh.
• Tariff matters more than region – switching to a better tariff gains 20–50% more savings than moving to a sunnier region.
• Use the calculator – for your exact postcode, not just regional averages.

Ready to see your postcode's potential? Run the calculator.