How much electricity do solar panels generate in Cardiff?

About 1,002 kWh a year for each kW of panels, for a roof-mounted, south-facing array at a 30° pitch with 14% system losses (PVGIS). A 2.7 kW system would generate about 2,700 kWh in its first year. Shade, a different roof angle or an east or west-facing roof will change this.

How long do solar panels take to pay back in Cardiff?

About 6.3 years for a 2.7 kW system costing £4,795 (the government’s median price for 0–4 kW systems), in a home using 2,700 kWh a year at Cardiff’s unit rate of 26.55p. It saves about £717 in the first year. That assumes the home uses all the electricity the panels generate, prices rise 3% a year and output falls 0.5% a year; exported electricity is counted at zero. At the Great Britain average unit rate of 26.32p, payback would be 6.3 years.

What is the electricity unit rate in Cardiff?

Under the Ofgem price cap for October to December 2026, single-rate electricity paid by Direct Debit costs up to 26.55p per kWh in the Southern Wales region, against a Great Britain average of 26.32p. The cap is the maximum for a standard variable tariff, so your own unit rate may be lower or higher on a fixed deal: use the rate on your bill in the calculator if you can.

How does Cardiff compare with nearby towns and cities?

Of the 5 nearest towns and cities we cover, Bristol (26 miles away) gets the most sun at 985 kWh per kW, and Birmingham (88 miles away) the least at 932 kWh. Cardiff gets 1,002 kWh, more than any of them. Within the Southern Wales price cap region, it ranks 1st of the 3 towns and cities we cover.

Where do these figures come from?

Solar generation is from the European Commission’s PVGIS 5.3 tool for Cardiff’s ONS centre point, checked on 2026-11-11. The unit rate is from Ofgem’s price cap tables, the installed price from the Department for Energy Security and Net Zero’s solar PV cost data, and typical use from Ofgem. Each figure is listed with its source link at the bottom of this page.

Solar panels in Cardiff: generation, savings and payback

Solar panels in Cardiff generate about 1,002 kWh a year for each kW installed, 4% more than the average of the 100 towns and cities in our data (960 kWh). Among the 3 places we cover in Ofgem’s Southern Wales region, it ranks 1st of 3 for solar output, against an average there of 990 kWh.

Cardiff is in Ofgem’s Southern Wales price cap region, where the unit rate for single-rate electricity paid by Direct Debit is 26.55p per kWh for October to December 2026: 0.23p above the Great Britain average of 26.32p.

For a home in Cardiff using Ofgem’s typical 2,700 kWh a year, a 2.7 kW system would cover a year’s use. At the government’s median installed price for 0–4 kW systems it would cost about £4,795, save about £717 in its first year and pay for itself in about 6.3 years. With the average sunshine of the 100 towns and cities in our data (960 kWh per kW), the same home would need a 2.8 kW system and pay back in 6.5 years, so Cardiff’s sunshine takes about 0.3 years off payback.

A typical home in Cardiff

System size: 2.7 kW; Sized to cover 2,700 kWh a year
First-year generation: 2,700 kWh
First-year savings: £717; At 26.55p per kWh
Savings over 25 years: £24,438; Prices rising 3% a year
Installed cost: £4,795; Government median for 0–4 kW systems
Payback: 6.3 years

Assumes all the electricity the panels generate is used at home, up to the home’s yearly use, and that panel output falls 0.5% a year. Power sent to the grid is counted at zero.

How Cardiff compares

Cardiff compared with the Southern Wales and Great Britain averages
	Cardiff	Southern Wales region average	Great Britain average
Solar output, kWh per kW a year	1,002	990	960
Electricity price per kWh	26.55p	26.55p	26.32p
System size for a typical home	2.7 kW	2.7 kW	2.8 kW
First-year savings	£717	£717	£711
Payback	6.3 years	6.3 years	6.6 years

Averages are of the 3 places in Southern Wales and the 100 towns and cities in our data, unweighted. The Great Britain column uses the Great Britain average price as well as the average sunshine.

Your home in Cardiff

All amounts in pounds sterling.

Your home

Nearest town or city

Sets how much electricity each kW of panels generates in a year where you live.

Electricity use

kWh per month

Check your bill or your supplier’s app for kWh used. Average the last 12 months if you can.

Electricity unit rate

pence per kWh

Starts at the Ofgem price cap unit rate for the Southern Wales region (Direct Debit, October to December 2026). Your bill shows your own unit rate.

Solar system

System size

Leave blank to size the panels to cover your yearly use, or enter the size on your quote.

Installed price

Use published medianPrice per wattTotal quoted price

£1.78 per watt: the median for 0–4 kW systems in the latest government cost data. Your quote may differ.

Assumptions you can change

Panel output loss

% per year

Starts at 0.5%, the median of nearly 2,000 reported rates in an NREL review.

Electricity price change

% per year

A scenario, not a forecast. Try 0% and 5% to see how much it matters.

Used directly at home

Share of the panels’ output your home uses as it is generated. 100% assumes all of it replaces electricity you would otherwise buy, up to your annual use.

Add a home battery

A battery only adds savings when you use less than 100% of your solar power directly. Lower “Used directly at home” under assumptions to model that.

Results

Payback period

6.3years

Cumulative savings first cover the installed cost during year 7.

Installed cost: £4,795; Published median for 0–4 kW systems
First-year savings: £717
Savings over 25 years: £24,438
Net gain after 25 years: £19,643
Return over 25 years: 410%; Net gain as a share of the installed cost
System size: 2.7 kW; Sized to cover your yearly use
First-year generation: 2,700 kWh

Cumulative savings over 25 yearsThe line crosses the installed cost in year 7: that is when the system has paid for itself.

Year-by-year table

Generation and savings for each of the 25 years
Year	Generation (kWh)	Price per kWh	Saved that year	Saved so far	Net position
1	2,700	£0.266	£717	£717	-£4,078
2	2,687	£0.273	£735	£1,452	-£3,344
3	2,673	£0.282	£753	£2,204	-£2,591
4	2,660	£0.290	£772	£2,976	-£1,819
5	2,646	£0.299	£791	£3,767	-£1,028
6	2,633	£0.308	£810	£4,577	-£218
7	2,620	£0.317	£831	£5,408	£613
8	2,607	£0.327	£851	£6,259	£1,464
9	2,594	£0.336	£872	£7,132	£2,336
10	2,581	£0.346	£894	£8,026	£3,230
11	2,568	£0.357	£916	£8,942	£4,147
12	2,555	£0.368	£939	£9,881	£5,086
13	2,542	£0.379	£962	£10,843	£6,048
14	2,530	£0.390	£986	£11,830	£7,035
15	2,517	£0.402	£1,011	£12,840	£8,045
16	2,504	£0.414	£1,036	£13,876	£9,081
17	2,492	£0.426	£1,062	£14,938	£10,143
18	2,479	£0.439	£1,088	£16,026	£11,231
19	2,467	£0.452	£1,115	£17,141	£12,346
20	2,455	£0.466	£1,143	£18,284	£13,489
21	2,442	£0.480	£1,171	£19,455	£14,660
22	2,430	£0.494	£1,200	£20,656	£15,860
23	2,418	£0.509	£1,230	£21,886	£17,091
24	2,406	£0.524	£1,261	£23,146	£18,351
25	2,394	£0.540	£1,292	£24,438	£19,643

Savings count only electricity your home no longer buys. Power sent to the grid is valued at zero. Grid emissions data has not been verified yet, so no carbon figure is shown. See the methodology for every formula and source.

Nearby towns and cities

Place	Distance	kWh per kW a year	Price per kWh	Payback
Bristol	26 miles	985	26.58p	6.4 years
Birmingham	88 miles	932	25.60p	6.9 years
Coventry	95 miles	950	25.36p	6.9 years
Leicester	117 miles	944	25.36p	6.9 years
Derby	122 miles	938	25.36p	6.9 years

Solar panels in Cardiff: questions

How much electricity do solar panels generate in Cardiff?: About 1,002 kWh a year for each kW of panels, for a roof-mounted, south-facing array at a 30° pitch with 14% system losses (PVGIS). A 2.7 kW system would generate about 2,700 kWh in its first year. Shade, a different roof angle or an east or west-facing roof will change this.
How long do solar panels take to pay back in Cardiff?: About 6.3 years for a 2.7 kW system costing £4,795 (the government’s median price for 0–4 kW systems), in a home using 2,700 kWh a year at Cardiff’s unit rate of 26.55p. It saves about £717 in the first year. That assumes the home uses all the electricity the panels generate, prices rise 3% a year and output falls 0.5% a year; exported electricity is counted at zero. At the Great Britain average unit rate of 26.32p, payback would be 6.3 years.
What is the electricity unit rate in Cardiff?: Under the Ofgem price cap for October to December 2026, single-rate electricity paid by Direct Debit costs up to 26.55p per kWh in the Southern Wales region, against a Great Britain average of 26.32p. The cap is the maximum for a standard variable tariff, so your own unit rate may be lower or higher on a fixed deal: use the rate on your bill in the calculator if you can.
How does Cardiff compare with nearby towns and cities?: Of the 5 nearest towns and cities we cover, Bristol (26 miles away) gets the most sun at 985 kWh per kW, and Birmingham (88 miles away) the least at 932 kWh. Cardiff gets 1,002 kWh, more than any of them. Within the Southern Wales price cap region, it ranks 1st of the 3 towns and cities we cover.
Where do these figures come from?: Solar generation is from the European Commission’s PVGIS 5.3 tool for Cardiff’s ONS centre point, checked on 2026-11-11. The unit rate is from Ofgem’s price cap tables, the installed price from the Department for Energy Security and Net Zero’s solar PV cost data, and typical use from Ofgem. Each figure is listed with its source link at the bottom of this page.

Sources for this page

Solar output for Cardiff: re.jrc.ec.europa.eu (checked 2026-11-11)PVGIS 5.3 outputs.totals.fixed.E_y for a 1 kW system. Radiation database PVGIS-SARAH3, years 2005-2023.
Southern Wales unit rate: www.ofgem.gov.uk (checked 2026-11-10)Southern Wales: electricity unit rate, single rate, Direct Debit, October to December 2026. Published as 26.55 pence per kWh.
Great Britain average price: www.ofgem.gov.uk (checked 2026-11-10)Great Britain average: electricity unit rate, single rate, Direct Debit, October to December 2026. Published as 26.32 pence per kWh.
Price cap region: www.ofgem.gov.uk (checked 2026-11-10)Nearest postcode to the town's ONS centroid is CF14 3UB (postcodes.io: https://api.postcodes.io/postcodes?lon=-3.188358964163832&lat=51.49977610454195&radius=2000&limit=1). Ofgem's postcode lookup puts district CF14 in the Southern Wales region.
Typical household use: www.ofgem.gov.uk (checked 2026-11-10)Revised TDCV, Electricity Profile Class 1, Medium: 2,700 kWh (decision of 25 May 2023, in use from 1 October 2023).
Installed price, 0–4 kW: assets.publishing.service.gov.uk (checked 2026-11-10)Column "0-4 kW: Median (£/kW)", 2025/26. Published as 1,780.25 £/kW.
Panel output loss: docs.nlr.gov (checked 2026-11-10)Median of nearly 2,000 reported degradation rates: "a median value of 0.5%/year" (average 0.8%/year).
Location: services1.arcgis.com (checked 2026-11-11)ONS Built Up Areas (December 2022) GB, W45000596: LAT/LONG fields.

Methods and every other figure are on the methodology page.