How Many Southampton Homes Have Solar Panels?The 2024 figures — and the number that matters more than the count
Southampton reached 4,745 solar PV installations at the end of 2024, 45% more than four years earlier. But Portsmouth grew at nearly twice that rate, and the average Southampton system is two-thirds the size of its neighbour’s. Here is what the figures show, and what a Southampton roof produces.
- 4,745 solar PV installations in Southampton at the end of 2024, up from 3,273 in 2020 (DESNZ)
- That is +45% in four years; Portsmouth managed +82% from a smaller base
- Average Southampton system: 3.9 kW, against 5.9 kW in Portsmouth — a housing-stock story
- A 4 kW south-facing array in Southampton models at 4,255 kWh a year (PVGIS)
- At Oct–Dec 2026 rates that is worth roughly £693–£876 a year, depending on how much you use at home
Southampton added 1,472 solar installations in four years
The Department for Energy Security and Net Zero publishes solar PV counts for every local authority. Southampton went from 3,273 installations at the end of 2020 to 4,745 at the end of 2024 — 1,472 more roofs, a rise of 45%. Total installed capacity is 18.3 MW.
That sounds like a lot until you look next door. Portsmouth went from 1,543 to 2,811 over the same four years — a rise of 82%, nearly twice Southampton’s rate, from a much smaller base.
| Southampton | Portsmouth | |
|---|---|---|
| Installations, end of 2020 | 3,273 | 1,543 |
| Installations, end of 2024 | 4,745 | 2,811 |
| Growth over four years | +45% | +82% |
| Total capacity | 18.3 MW | 16.7 MW |
| Average system size | 3.9 kW | 5.9 kW |
DESNZ, Renewable electricity by local authority 2014–2024.
The interesting number is the average system size
Southampton has 1,934 more installations than Portsmouth but only 1.6 MW more capacity, because the average Southampton system is 3.9 kW against Portsmouth’s 5.9 kW. Two-thirds the size, roughly.
That gap is about housing rather than ambition. Southampton has a far larger share of flats and small terraces, and a roof is a roof: a two-bedroom terrace in Shirley or Portswood has room for eight or ten panels, not eighteen. UK House Price Index figures for July 2026 put the average Southampton property at £235,977, with flats at £152,827 — a housing stock skewed towards smaller dwellings, and the panel count follows.
The practical read-across: if you live in a Southampton terrace, do not judge a quote against a headline figure written for a detached house in the New Forest. Judge it against what your roof can hold.
What a Southampton roof actually produces
PVGIS, the European Commission’s modelling tool, puts a 4 kWp south-facing array at 35 degrees in Southampton at 4,255 kWh a year. Portsmouth, a few miles east and closer to the water, models at 4,525 kWh — about 6% more, which is a real difference but not one worth moving house over.
| A 4 kW array in Southampton | Figure |
|---|---|
| Modelled output (PVGIS) | 4,255 kWh a year |
| Worth it, if you use 30% at home | £693 a year |
| Worth it, if you use 60% at home | £876 a year |
| South East average cost, up to 4 kW | £7,436 |
| Simple payback | about 8–11 years |
PVGIS 5.3 (PVGIS-SARAH3), 4 kWp south at 35°, 14% system loss. Values use the Ofgem price cap for 1 Oct–31 Dec 2026 (26.32p/kWh) and the 12p/kWh Outgoing Octopus export rate. Cost: DESNZ 2025/26 South East mean of £1,859/kW for systems up to 4 kW. Your quote follows a survey.
The spread between those two savings figures is the whole game. The same array is worth £693 a year if you export most of what you make, and £876 if you use most of it at home — because every unit you use yourself is worth 26.32p and every unit you export is worth 12p. That is what a battery, a timer on the immersion, or simply being in during the day is actually buying you.
What this means if you are thinking about it
Southampton is not short of solar, and it is not short of installers either. What the figures suggest is that the city’s roofs are smaller than the national conversation assumes, so the questions worth asking are about panel count, shading from neighbouring buildings and whether a battery earns its keep on your usage — not about headline system sizes.
If you want that worked through for your own roof, our page on solar panels Southampton covers costs, the conservation areas, and how a survey here actually runs.
Frequently Asked Questions
How many homes in Southampton have solar panels?
DESNZ counted 4,745 solar PV installations in Southampton at the end of 2024, up from 3,273 at the end of 2020 — a rise of 45%. Total installed capacity is 18.3 MW, which works out at an average of about 3.9 kW per installation.
Why are Southampton solar systems smaller than Portsmouth ones?
Roof size. Southampton averages 3.9 kW per installation against Portsmouth’s 5.9 kW, and the city has a larger share of flats and small terraces. UK House Price Index figures for July 2026 put the average Southampton property at £235,977 and flats at £152,827 — a housing stock skewed to smaller dwellings, and panel counts follow roof area.
How much electricity do solar panels produce in Southampton?
PVGIS models a 4 kWp south-facing array at 35 degrees in Southampton at 4,255 kWh a year. Portsmouth models slightly higher at 4,525 kWh. Shading from neighbouring buildings usually matters more than the few miles between them.
Are solar panels worth it in Southampton?
On the Oct–Dec 2026 price cap a 4 kW Southampton array is worth roughly £693 a year if you use 30% of the generation at home, or £876 if you use 60%. Against the DESNZ South East average cost of £7,436 for 4 kW, that is a simple payback of about 8 to 11 years.
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