The State of UK Commercial Rooftop Solar 2026

How big is the opportunity?

Across England & Wales, Sunseam ranks 133,996 commercial buildings of 1,000 m² or more. Fitted with rooftop solar they could host an estimated 39,010 MWp of generation and cut bills by about £5.7bn a year, while displacing roughly 7.7m t of CO₂ annually.

Why now, economics first, EPC second

The primary driver is economics: rising commercial electricity and grid charges against a typical rooftop-solar payback of about 4–9 years mean the value is there to capture today. On top of that, around 30% of these buildings sit at EPC Band D–G (39,816roofs). The minimum to let is Band E now; the government's long-term MEES target is EPC B for large non-domestic buildings (over 1,000 m²), expected ~2031, so the biggest, lowest-rated roofs also have a future-proofing reason to act, and solar both cuts bills and lifts a building's rating. (The previously proposed 2027 “Band C” commercial step was dropped in 2026.)

FAQ

Methodology

Sunseam analysis of official UK public data. Figures are estimates, not measured values or guarantees. We include non-domestic buildings of 1,000 m² or more, de-duplicated to the latest record per building, and exclude roofs already fully covered by solar. Roofs with a partial system are included and ranked on the space that remains. System size is type-aware (single-storey sheds ≈ full roof, multi-storey ≈ less) at ~7 m²/kWp; generation uses location-specific annual yield from the European Commission's PVGIS on 98% of roofs (bounded 700–1150 kWh/kWp/yr) and a typical ~950 kWh/kWp/yr on the rest; benefit uses a £0.28/kWh import price and £0.08/kWh export, with self-consumption modelled per building (it varies with daytime load), the avoided-bill saving is capped at each building's own bill and export income is counted separately on top; CO₂ uses ~0.207 kgCO₂/kWh applied to generation at the typical yield. England & Wales only. Contains Ordnance Survey data © Crown copyright and database right 2026. Contains HM Land Registry and Energy Performance of Buildings data © Crown copyright and database right 2026, licensed under the Open Government Licence v3.0. Solar yield data: PVGIS © European Union, 2001–2026.

Shared roof outlines. Our capacity estimates are under revision. Where several adjoining units share one mapped roof outline, or where no outline could be matched and we size from floor area instead, an individual estimate can be too high or too low. We are rebuilding how roof size is measured and will restate the affected figures once that work is complete. Roof counts, energy ratings and ownership figures are unaffected.