Solar panel payback in Wales
The short answer
- 11.4 years to pay back a typical 4 kW south facing system in Wales, earning about £526 a year
- About £6,390 left over 25 years after the £6,000 cost, or about £1,360 with a battery
- 13.9 years on an east or west roof, and 8.8 years on a 17.5p export rate
Updated 25 September 2026. Every figure on this page comes from our published model; see where our data comes from.
A typical 4 kW solar system in Wales costs about £6,000, generates about 3,540 kWh a year and brings in about £526 a year in bill savings and export payments, so it pays for itself in about 11.4 years. These are the solar calculator's figures for all of Wales.
Payback by system size
About 11.4 years for 4 kW. Systems above 4 kW earn more over 25 years but pay back more slowly, because more of their output is exported at 12p rather than used at 26.32p.
| System | Installed cost | Generation a year | Saving and export a year | Payback | 25 years, after costs |
|---|---|---|---|---|---|
| 3 kW | £4,000 to £5,500 | 2,655 kWh | £414 | 11.5 years | £5,002 |
| 4 kW | £5,000 to £7,000 | 3,540 kWh | £526 | 11.4 years | £6,390 |
| 5 kW | £6,500 to £8,500 | 4,425 kWh | £639 | 11.7 years | £7,552 |
| 6 kW | £8,500 to £10,000 | 5,310 kWh | £752 | 12.3 years | £8,464 |
The data behind this table
South facing roof at a typical pitch, a household using 2,500 kWh a year (a bill of about £860) that is out for about half the day, no battery, 12p export on Outgoing Octopus. Payback uses the middle of each cost range; 0% VAT until 31 March 2027. The 25 year figure allows for the panels losing 0.5% of their output a year.
Roof direction
South is best, but east or west still pays back in about 13.9 years. A north facing roof makes much less and takes about 19 years.
| Roof faces | Generation a year | Saving and export a year | Payback |
|---|---|---|---|
| South | 3,540 kWh | £526 | 11.4 years |
| South-east | 3,363 kWh | £500 | 12 years |
| South-west | 3,292 kWh | £494 | 12.1 years |
| East | 2,832 kWh | £433 | 13.9 years |
| West | 2,832 kWh | £433 | 13.9 years |
| North | 1,947 kWh | £315 | 19 years |
With a battery
A battery slows payback to 21.6 years here. It adds about £177 a year for £4,600, and a battery lasts 10 to 12 years, so it is bought twice over the life of the panels.
| Result | Panels only | With a 5 kWh battery |
|---|---|---|
| Upfront cost | £6,000 | £10,600 |
| Used at home | 20% of output | 55% of output |
| Saving and export a year | £526 | £703 |
| Payback | 11.4 years | 21.6 years |
| 25 years, after costs | £6,390 | £1,360 |
Export tariff
The export rate moves payback more than where you live. The same system pays back in 8.8 years at 17.5p and 19.9 years at 4.1p.
| Export rate | Saving and export a year | Payback |
|---|---|---|
| 4.1p flat SEG rate | £302 | 19.9 years |
| 12p, Outgoing Octopus | £526 | 11.4 years |
| 17.5p installer-linked rate | £682 | 8.8 years |
Month by month
May makes about 4.0 times as much as December. April to September carries most of the year's output, so no home battery covers a winter in Wales.
| Month | kWh |
|---|---|
| January | 126 |
| February | 184 |
| March | 304 |
| April | 406 |
| May | 449 |
| June | 444 |
| July | 438 |
| August | 384 |
| September | 326 |
| October | 223 |
| November | 146 |
| December | 111 |
Compared with other regions
The whole of Great Britain pays back within about two years of each other. Roof direction and the export tariff matter more than the region.
| Region | Generation a year | Saving and export a year | Payback |
|---|---|---|---|
| South and East England | 3,780 kWh | £556 | 10.8 years |
| The Midlands | 3,540 kWh | £526 | 11.4 years |
| North England | 3,400 kWh | £505 | 11.9 years |
| Wales | 3,540 kWh | £526 | 11.4 years |
| Scotland | 3,180 kWh | £477 | 12.6 years |
Work out your own roof, system size and battery in the solar panel calculator, or read solar panel payback in the UK.
Frequently asked questions
How long do solar panels take to pay back in Wales?
About 11.4 years for a typical 4 kW south facing system costing £6,000, at the October 2026 price cap and a 12p export rate. It earns about £526 a year and leaves about £6,390 over 25 years.
Are solar panels worth it in Wales?
On a reasonable roof, yes: a 4 kW system pays for itself in about 11.4 years, well inside a 25 year panel life. An east or west roof takes about 13.9 years, and a battery stretches it to 21.6 years.
How much electricity does a 4 kW solar system make in Wales?
About 3,540 kWh a year on a south facing roof, using 885 kWh per kW: the PVGIS figure for homes across the region, less 7% for shading and dirt. Enter your postcode in the solar calculator for your own area. May makes about 4.0 times as much as December.
Data sources
- European Commission Joint Research Centre, PVGIS 5.3: generation by region and month, queried September 2026.
- MCS, MGD 003 Solar PV Self-Consumption: the share of output used at home.
- Ofgem price cap October to December 2026; export rates from the suppliers, 25 September 2026; costs checked against DESNZ solar PV cost data, May 2026.
- Map: Office for National Statistics, ITL1 boundaries January 2025, Open Government Licence v3.0. Contains OS data © Crown copyright and database right 2025.