Solar panels in London: output, grid and planning

How much power solar makes in London

London sits in the sunnier south of the country. PVGIS is the European Commission’s solar tool. It models about 1,020 kWh a year for every kWp on a south-facing roof tilted at 35 degrees. We used the PVGIS calculation for central London, which assumes a 14% system loss.

The best tilt here is around 40 degrees, which models at about 1,024 kWh per kWp. That gap is tiny. A normal roof pitch therefore loses almost nothing against the ideal angle.

Here is a worked example. A 4 kWp system makes about 4 x 1,020, or 4,080 kWh a year.

Ofgem treats 2,500 kWh a year as typical use for a medium home. Still, this is a modelled estimate, not a promise. How much you use yourself depends on when you are at home.

Three things move the number most. Orientation comes first, because east or west roofs make less than south ones. Shade from taller buildings, chimneys and trees can also cut output sharply. Tilt matters least, as the figures above show.

Roofs, terraces and flats

Many London homes are terraced houses or flats. Roof space can be tight, and a neighbour’s wall may throw shade across the panels. However, a good survey will model that shade before you commit.

A surveyor should also check the roof itself. MCS requires a suitably competent person to confirm the roof structure can take the load. This matters most on older terraces, because roofs vary a lot in age and build.

If you live in a flat, you may need your freeholder’s consent as well. Our post on solar panels for terraced houses and flats covers shared roofs and leasehold questions in more detail.

Grid connection in London

Most of London connects to the grid through UK Power Networks, which runs the London Power Networks area. Your network operator must know about any new generator. The rules depend on size.

A system up to 16 A per phase follows the G98 route. Anything above 16 A per phase follows G99. MCS says the 16 A figure counts all generators together. A battery added to solar can therefore push a home into G99.

The same MCS standard says the installer makes the notification. Even so, ask who will send it and when. Keep the confirmation with your paperwork.

Planning in London

Planning here sits with your borough council. There are 32 boroughs plus the City of London, and each has its own planning team. Planning Portal is the national starting point.

England’s permitted development rules for domestic solar changed on 27 August 2026. The Planning Portal explains the changes, including a split between houses and blocks of flats. Projects that no longer qualify can still use the older rules until 26 August 2027.

Plug-in solar is now covered by the planning rules too. GOV.UK describes these panels as under 800W and plugged into a domestic socket. Planning Portal says they cannot go on wooden structures or cladding, because of fire risk.

London has many conservation areas and listed buildings, and both carry extra limits. Flats follow separate rules again. Ask your borough before you pay a deposit.

Choosing an installer

Look for an installer certified under MCS, the UK quality mark for small-scale renewables. MCS matters for money too, because you must show it to claim payments under the Smart Export Guarantee. Our guide to the Smart Export Guarantee explains how those payments work and how to compare tariffs.

Check whether the firm also belongs to the Renewable Energy Consumer Code. RECC members must insure deposits, stage payments and workmanship warranties. That protects you if the installer stops trading.

DESNZ publishes cost data from MCS records. Its 2025/26 figures show a median of about £1,780 per kW of declared net capacity for 0-4 kW installs. That covers Great Britain, includes VAT where it applied and excludes batteries.

Next, get at least three written quotes. Compare panel size, brand, warranty length and what each price includes. Our page on solar panel installation shows what a full job covers. For prices, the solar panel costs guide draws on official data.

If you are west of the city, it is worth reading about solar installers serving Reading. That area has a different network operator.

When you are ready, you can ask for MCS-certified quotes through this site. Your details are only passed on with your consent.