Quick answer: solar panels in London make about 1,025 kWh per kWp a year, so a 4 kWp system makes about 4,100 kWh. That sits towards the top of the UK range. Fitting costs more here than in most regions, and flats and conservation areas bring extra rules.
This guide to solar panels in London covers yield, costs, planning and the housing types you will meet, since each shapes what is practical. Prices and rates are as at October 2026. For the basics, see how a domestic solar system fits together.
How much do solar panels make in London?
London sits in the sunnier south-east of England. The PVGIS model gives 1,025 kWh per kWp a year, about 4% above the UK reference of 990.
A 4 kWp system uses 9 or 10 panels and makes about 4,100 kWh a year. Since that is well above the 2,700 kWh a typical home uses, exports are significant. All figures assume south-facing panels at a 35° tilt.
Roof direction matters, however. A south-east roof gives about 95% of the south-facing figure, and south-west gives 93%. East or west roofs make about 80%, and north-facing roofs only about half.
Seasonal swings are smaller than in the north. For example, in December, London makes about 37.5 kWh per kWp, against about 122.5 in June. That is roughly 31%. See solar panel calculator to turn this into your own estimate.
Sources: PVGIS v5.2 (PVcalc, SARAH2 database, 14% losses, retrieved October 2026).
What a 4 kWp system saves in London
On our standard model, with 30% self-use, 26.32p import and a 12p export rate, a 4 kWp system saves and earns about £670 a year. That gives a payback of about 11 years at a cost of £7,500.
The 12p export rate is only available if you also buy your electricity from the same supplier. In contrast, open-market rates run closer to 3–6p, which would lengthen payback. Our page on typical UK solar costs and payback sets out the full model and its limits.
Solar panel costs in London
London is the most expensive region in the government’s cost data. For 2025/26, the mean for installs up to 4 kW was £2,101 per kW, covering all installs and including VAT. At that rate, 4 kW costs about £8,400.
That sits at the top of our UK range of £6,500–£8,500 for a 4 kWp system. Meanwhile, scaffolding, awkward access and roof complexity can all add to a London quote. See what fitting solar panels costs for the full breakdown.
The zero rate of VAT lasts until 31 March 2027, although 5% returns after that.
Sources: DESNZ solar PV cost data; HMRC VAT manual.
Planning rules for solar panels in London
Because London is in England, the rules that came into force on 27 August 2026 apply. Rooftop solar on a house is usually permitted development. On a pitched roof, panels can project no more than 200 mm and must not sit above the highest part of the roof.
On a flat roof, the highest part can be up to 600 mm above the roof. Since rear extensions often have flat roofs, this matters. Our guide to solar on a flat roof covers mounting and angle.
Panels can also go on walls and balconies, within 200 mm where the wall faces a road and 400 mm elsewhere. Listed buildings are not permitted development. Panels on a wall or balcony that fronts a road in a conservation area also need consent.
London has many conservation areas, and some boroughs use Article 4 directions that remove permitted development rights. Therefore, check with your council before you order.
Sources: SI 2026/896.
Terraces, flats and conservation areas
Typical London homes are Victorian and Edwardian terraces, converted flats and mansion blocks. Each raises a different question, because each has a different roof.
Terraces often have small roof slopes and some shade, so ask for a shading survey. Conversions and blocks are often leasehold, so the roof typically belongs to the freeholder. You need consent before any panels go up.
If visible panels are restricted, some owners look at integrated solar roof tiles. Ask your council whether tiles are treated the same way as panels.
Plug-in solar for London flats
Since 27 August 2026, plug-in kits of up to 800 W output can legally be used in Great Britain. However, you must tell your network operator, use only one kit per home, and never use an extension lead.
They are not permitted development on a wooden wall, balcony or fence, while renters and leaseholders should get landlord or freeholder consent first. Our guide to plug-in balcony solar kits explains the rules.
Sources: SI 2026/848.
Buying a London home with panels
If the London home you are buying already has panels, check who owns them, whether they are MCS-certified, and what paperwork transfers. Our guide to what to check when a home comes with panels has a checklist.
Birds are an urban problem too, so see keeping pigeons out from under panels if a roof has a regular flock.
Grants and schemes in London
There is no general grant for solar in London. However, the government’s Warm Homes Plan promises loans for solar and batteries, mostly from 2027. Check gov.uk before you apply.
Councils may also run a Warm Homes: Local Grant for low-income households. Ask your borough directly. For the national picture, see solar panel costs and savings.
Next steps
If you are comparing regions, see what solar generates in Bristol, because it comes out very close to London. For another view, read about Birmingham solar costs and support. When ready, get quotes from local installers with the form below.