Do I need planning permission for solar PV in London?

Usually no — most installs are permitted development. Article 4 directions in conservation areas (Hampstead, Hackney, Camden, Islington, RBKC) remove PD rights and require full planning. Always check the conservation area boundary before commissioning install.

Is solar PV worth it with current electricity prices?

Yes for most south- or east-west-facing London roofs. Current electricity at 28p/kWh and SEG export at 15p/kWh give a typical 4kW system payback of 8–10 years and lifetime savings of £18,000–£25,000 over 25 years. Battery storage shortens payback further for users with high evening use or EV charging.

How long does solar PV install take?

On site: 1–2 days for a 4–6kW system; 2–3 days for 10kW or with battery. Scaffolding usually erected the day before. DNO notification and grid connection 4–6 weeks before install on systems over 3.68kW. Total project timeline: 6–10 weeks from order to commissioning.

Does Builderr install solar PV?

Yes — included in whole-house renovation and extension contracts, or as a standalone service. MCS-certified install team, design and commissioning included. Battery storage and EV charge point bundled where required.

Solar PV Retrofit Cost London 2026 | Builderr

How Much Does Solar PV Retrofit Cost on a London House?

Solar PV retrofit in London costs £6,500–£9,500 for a 4kW system (10–12 panels), £8,500–£12,500 for 6kW (14–18 panels), and £14,000–£20,000 for 10kW (24–30 panels). Battery storage adds £5,000–£12,000. Payback 8–14 years on current export tariffs (15p SEG) and electricity prices. MCS-certified install required for grid export.

Cost breakdown

4kW system (10–12 × 400W panels, 4kW inverter): £6,500–£9,500 supplied and installed by MCS-certified contractor. 6kW (14–18 panels, 5kW hybrid inverter): £8,500–£12,500 — typical for a 3-bed terrace with average electricity use. 10kW (24–30 panels, 8kW hybrid inverter): £14,000–£20,000 — larger family home or planned EV/heat pump load. Battery storage (10kWh): £5,000–£8,000; (15kWh): £7,000–£10,000; (20kWh): £9,000–£12,000. EV charge point bundled at install: £800–£1,200. Hardware brands: panels Trina, Longi, REC, JA Solar; inverters Solis, Growatt, Solax, Tesla Powerwall, Givenergy; mounting GSE In-Roof, Renusol, Schletter. Scaffolding £600–£1,500 included on most quotes.

Planning and structural considerations

Permitted development: most London solar PV installs are PD provided panels are flush with the roof, do not project above the ridge, and do not project more than 200mm from the roof slope. Conservation areas (Hampstead, Hackney, Camden, RBKC): PD is removed by Article 4 directions — full planning required. Listed buildings: always need Listed Building Consent. Structural assessment: confirm roof can carry the additional 12–20 kg/m² load — usually fine on a Victorian or modern roof, but worth a structural engineer's opinion on heavy slate roofs or older timber structure. Scaffold and access: terraced houses with rear access only typically need a scaffold lift and gantry to get panels onto the roof; cost included in quote.

Payback and yield in London

Generation: London 4kW system generates 3,200–3,800 kWh per year (south-facing, no shading); 4kW east-west split generates 2,800–3,400 kWh. Self-consumption: typical home uses 25–40% of generation directly without battery; with 10kWh battery, self-consumption rises to 70–85%. Export: surplus exported via Smart Export Guarantee (SEG) at 15p/kWh (Octopus Outgoing) — current best London rate. Savings: typical 4kW system saves £700–£1,100/year on a 3-bed terrace at current electricity prices (28p/kWh); 6kW system saves £950–£1,500/year; 10kW with battery saves £1,400–£2,200/year. Payback: 8–14 years before any maintenance cost. System lifespan: panels 25-year warranty, 30-year linear power warranty; inverters 10–12 years; batteries 10 years.