Metered, not modelled
Solar output in Cardiff
736–870 kWh per kWp a year
the middle half of 147 real Cardiff systems, measured over 2024
- Systems measured 147
- Median 800
- Best 10% of roofs 921
- Rank of 49 areas 17th
- Typical system size 3.1 kWp
A typical 4 kWp system here made roughly 2,940 to 3,480 units of electricity last year.
Not a forecast. 147 solar systems around Cardiff were metered through 2024, and the middle half made 736 to 870 kWh for every kWp of panels.
The best tenth reached about 921 kWh per kWp — some 20% clear of the British median of 766, and among the strongest roofs we can measure anywhere.
Only 69% of these systems face south, south-east or south-west, against 86% nationally — so part of what you see here is roof direction, not the sky.
That places Cardiff 17th of 49, ahead of 32 of the areas we can measure.
At the other end, the quietest tenth of systems here made about 642 kWh per kWp — usually shade, a poor direction, or both.
What none of it tells you is what your own roof would do. These systems point in every direction and some have been up for fifteen years.
The spread behind that number
Every Cardiff system, grouped by what it made, against Britain as a whole. The two shapes overlap heavily, which is the honest headline: your postcode nudges the result, your roof decides it.
Cardiff: the middle half of 147 systems made 736–870 kWh per kWp.
Is your roof right for solar?
Enter your postcode and we'll estimate your roof's direction, its solar potential, and show certified installers covering your area.
Areas near Cardiff
Neighbouring postcode areas we can also measure.
How Cardiff compares
Looking for someone to fit them? MCS-certified solar installers in Cardiff are listed in the Solarable directory.
Output figures from openclimatefix/uk_pv (Hugging Face, CC-BY-4.0), collected by Sheffield Solar. The British median is 766 kWh per kWp. How we measure.
Related
Keep going.
Check your roof
Address-based roof check. Postcode in, Solarable Report out.
Open →
How much electricity does a solar panel produce?
What a kWp really generates in Britain, modelled and metered.
Open →
Solar savings calculator
Annual benefit and payback in honest UK ranges.
Open →
How we measure
Our sources, our cross-checks, and what we refuse to publish.
Open →
How much sun does my roof get?
How sunlight falls on a UK roof, month by month.
Open →