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Big Roof Britain Solar Payback Index Standing Charge Drag

Big-Roof Britain

Some roofs fit twice the solar of others. We’ve ranked 2182 UK postcodes by how much a typical house roof can fit — and Northumberland leads the pack.

The results reveal a country divided — not by wealth, but by geometry. Rural roofs dwarf city terraces. NE44 (Northumberland) fits 9.2 kWp. MK1 (Milton Keynes)? Just 2.2 kWp.

What we found

The rural advantage

NE44 (Northumberland) tops the list at 9.2 kWp — enough for 19 modern solar panels. Runner-up NE20 (Northumberland) manages 8.7 kWp.

Wales punches above its weight

Welsh postcodes feature prominently near the top. Large plots, detached builds, and pitched roofs keep Wales competitive.

Cities struggle

110 postcodes were excluded — flat-heavy areas where individual roof access is rare. Even among houses, terraced city centres lag behind. Geometry is destiny.

Top 50 postcodes

Ranked by typical roof-fit capacity (kWp) for houses and bungalows. Click any postcode to visit its full page for payback calculations and quotes.

# Postcode Place Region Typical fit (kWp) ≈ Panels Median floor (m²)
1 NE44 Northumberland Northern 9.2 19 139
2 NE20 Northumberland Northern 8.7 18 132
3 GU25 Runnymede Southern 8.6 18 142
4 LL66 Isle of Anglesey North Wales and Mersey 8.3 17 120
5 SA32 Carmarthenshire South Wales 8.2 17 122
6 TD9 Scottish Borders Southern Scotland 8.1 17 107
7 LL70 Isle of Anglesey North Wales and Mersey 8.1 17 110
8 SA35 Pembrokeshire South Wales 8.1 17 117
9 PE35 King's Lynn and West Norfolk Eastern 7.8 16 126
10 CA19 Cumberland North West 7.8 16 121
11 KT24 Guildford South East 7.8 16 125
12 EX21 Torridge Southern Western 7.8 16 116
13 BS28 Somerset Southern Western 7.7 16 122
14 SA37 Pembrokeshire South Wales 7.6 16 115
15 SA66 Pembrokeshire South Wales 7.6 16 111
16 BH18 Bournemouth, Christchurch and Poole Southern 7.6 16 103
17 HP8 Buckinghamshire Southern 7.6 16 121
18 KT11 Elmbridge South East 7.5 16 127
19 CA5 Cumberland North West 7.5 16 115
20 TS22 Stockton-on-Tees Northern 7.5 16 122
21 LL73 Isle of Anglesey North Wales and Mersey 7.5 16 104
22 WR6 Malvern Hills Midlands 7.4 15 113
23 SA36 Pembrokeshire South Wales 7.4 15 112
24 B94 Stratford-on-Avon Midlands 7.4 16 119
25 LD5 Powys South Wales 7.4 15 116
26 LL74 Isle of Anglesey North Wales and Mersey 7.4 16 88
27 SA44 Ceredigion South Wales 7.4 16 108
28 HU14 East Riding of Yorkshire Yorkshire 7.3 15 115
29 LN10 East Lindsey East Midlands 7.3 15 96
30 NE69 Northumberland Northern 7.3 15 97
31 CH60 Wirral North Wales and Mersey 7.3 15 110
32 AL6 Welwyn Hatfield Eastern 7.2 15 116
33 CW6 Cheshire West and Chester North Wales and Mersey 7.2 15 117
34 LA20 Westmorland and Furness North West 7.2 15 118
35 HU20 East Riding of Yorkshire Yorkshire 7.2 15 107
36 WR7 Wychavon Midlands 7.2 15 111
37 NG23 Newark and Sherwood East Midlands 7.2 15 109
38 SA39 Carmarthenshire South Wales 7.2 15 106
39 CA4 Cumberland North West 7.2 15 111
40 SA42 Pembrokeshire South Wales 7.2 15 111
41 TN7 Wealden South East 7.2 15 117
42 LL64 Isle of Anglesey North Wales and Mersey 7.1 15 106
43 SG10 East Hertfordshire Eastern 7.1 15 116
44 SA62 Pembrokeshire South Wales 7.1 15 103
45 TN20 Wealden South East 7.1 15 116
46 GL19 Forest of Dean Midlands 7.1 15 111
47 SA33 Carmarthenshire South Wales 7.1 15 105
48 SA19 Carmarthenshire South Wales 7.1 15 110
49 LL37 Gwynedd North Wales and Mersey 7.1 15 107
50 BS40 North Somerset Southern Western 7.1 15 111

Admit it — you want to know where Britain’s smallest roofs are. They’re in MK1 (Milton Keynes) , averaging just 2.2 kWp.

Note: Flat-heavy areas (≥80% flats) or postcodes with fewer than 10 EPCs are excluded from the ranking.

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How we calculated this

What: Typical roof-fit capacity in kilowatts peak (kWp) per postcode, for houses and bungalows only.

How: We use Energy Performance Certificate (EPC) median floor area for each postcode, divide by typical storeys (2.0 for houses, 1.0 for bungalows), then apply roof geometry factors: one pitched slope (pitch factor 1.20), 50% usable for solar, minus 20% for obstructions (chimneys, skylights). Finally, we convert roofable area to kWp using modern 430W panels (≈4.2 m² per kWp).

Who’s in: Houses and bungalows (individual roof access).

Who’s out: Postcodes with ≥80% flats (shared roofs), or fewer than 10 EPC certificates (insufficient data).

Data & citing this work

Built using open Energy Performance Certificate data from the UK Government. PVGIS solar yield estimates from the European Commission. Postcode geography from ONS. All calculations transparent and reproducible.

How to cite: SolarByPostcode (2025). Big-Roof Britain: UK Postcode Solar Capacity Rankings. Retrieved from https://solarbypostcode.co.uk/insights/big-roof-britain/