Plug-In Solar London
The complete 2026 guide to balcony solar in London. Whether you're in a Hackney council flat, a Camden conversion, a Wandsworth new-build or a leasehold flat in Westminster — here's exactly what plug-in solar can deliver in the capital, what permissions you actually need, and what to buy.
London sun hours / year
~1,500
Heathrow Met Office data
Annual saving (800W kit)
£60–£90
London-specific estimate
Planning permission
Not needed
Non-fixed install
Listed/conservation
Check first
~25% of inner London
Why plug-in solar fits London like nowhere else
London is, on paper, the worst case for residential solar in the UK. Average annual sun hours hover around 1,500 — roughly 70–75% of what Cornwall sees. Roof orientations are constrained by terraces, planning rules in conservation areas restrict panel installation on the visible side of the roof, and most Londoners don't own the roof above their flat anyway.
Plug-in solar fixes every one of those problems. It doesn't need a roof. It doesn't need scaffolding. It doesn't need a south-facing aspect (south-east or south-west works fine, and even an east-facing balcony delivers most of the value if you're home in the morning). It doesn't need landlord consent in most rental scenarios under the Renters' Rights Act 2025. And because it plugs into a standard 13A socket, anyone with an outside-facing wall can install it.
That makes London — with its 3.6 million flats, dense rental market, and rapidly-rising electricity bills — arguably the single biggest plug-in-solar opportunity in the UK.
London-specific things to check before you buy
1. Conservation area or listed building?
Roughly a quarter of inner London is in a conservation area. Listed buildings are scattered everywhere. Plug-in solar mounted on a balcony rail or in a garden is generally fine because nothing is permanently fixed, but anything visible from the public realm in a conservation area can attract attention from the council. Check via your borough's planning portal — london.gov.uk tells you which borough you're in if you're unsure.
2. Leasehold flat?
Read your lease. Most leases say nothing specific about solar panels because they predate the technology, but they often have clauses about “alterations to the exterior.” A plug-in kit on a balcony with a non-permanent mount typically falls outside that — you're not altering anything — but a 30-second message to the freeholder or managing agent is worth it for peace of mind.
3. Older Victorian or Edwardian property?
London has a lot of pre-2008 wiring with Type AC RCDs in the consumer unit. Plug-in solar requires a Type B RCD. A simple visual check by a qualified electrician (£60–£100) tells you whether you're ready, or whether you need an upgrade first. Don't skip this.
4. Tower block or high-rise?
Building management often has policies on what can hang off a balcony. Many London tower blocks built since 2018 have explicit restrictions on anything mounted to the external railings — not because of solar specifically but because of fire-safety regulations following Grenfell. Check with your building manager before buying. Ground-floor flats with a small garden have no equivalent restrictions.
What an 800W kit actually delivers in London
A standard 800W plug-in kit in London — well-positioned on a south-facing balcony — produces around 650–750 kWh per year. At today's electricity prices (~28p/kWh), that's an annual saving of £60–£90 if you self-consume most of it.
The trick to maximising that number is matching consumption to generation. London plug-in solar peaks between 11am and 3pm in summer. If you can shift dishwasher cycles, EV charging, hot-water immersion heating, or air-conditioning to that window, you capture far more of the value than letting it spill back into the grid (which you typically don't get paid for on plug-in setups).
That's exactly what Sun Hours is built to help you do. Enter your London postcode — SW, SE, N, NW, E, W, EC, WC, all supported — and you get a 7-day forecast showing exactly when your panels will be at peak. Plan your high-draw appliances around that window and you'll squeeze the maximum value from a London-grade solar resource.
Forecast your London panels before they generate — for free.
Enter your London postcode (any of: SW, SE, N, NW, E, W, EC, WC, BR, CR, DA, EN, HA, IG, KT, RM, SM, TN, TW, UB, WD) and your kit size. Sun Hours gives you a 7-day kWh forecast and an hourly curve showing exactly when to run your washing, EV, or air-con. No account. No tracking.