Solar explained to clever people by people who are not trying to be clever

Solar Panels in PR8 (Sefton)

See if solar pays off for you in Sefton — price, savings and payback in under a minute (official UK data).

Solar Calculator

Change the settings below to see how costs and savings work for your situation.

System Size

Roof Direction

Battery Storage

Export Value

Your Numbers

Break-even
12.2 years
After this, it's pure profit
Upfront Cost
£12,207
What you pay to get started
Annual Benefit
£1,000
What you save every year
Profit Over 25 Years
£12,792
After paying itself off, you're this much ahead

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How we calculate this

Solar generation: Based on typical south-facing roof at 35° angle. We account for weather, dirt, and system losses (14%).

How much you'll use directly:

  • Without battery: You'll use about 40% of what you generate. The rest gets sold back to the grid.
  • With 5 kWh battery: You'll use about 70% (battery stores extra for evening use).
  • With 10 kWh battery: You'll use about 75% (more storage means less exported).
  • Panel-only payback: Bigger systems don’t shorten payback—cost and savings rise together per kW.
  • Battery & payback: Batteries raise self-use and cut bills, but added hardware cost often lengthens break-even at typical UK rates.
  • When a battery can still make sense:
    • Evening-heavy usage patterns
    • Time-of-use tariffs / cheap night rates
    • Low export rate vs. high unit rate
    • Heat pump or EV charging synergy
    • Optional backup/resilience (system-dependent)
    • Lower evening-hour CO₂ vs. grid

Costs: Battery prices are typically £700 per kWh. Export tariffs vary by supplier (usually 5–15p per kWh).

Grid connection: Systems up to about 3.7 kW typically need just a notification (G98). Larger systems may need permission (G99).

These are typical values based on average usage patterns. Your actual results will vary based on your roof, shading, and how you use electricity.

Your area in context

Read the full story

A typical roof here lands around 6.0 kW, with most eligible homes comfortably fitting within 3–6 kW. Each kilowatt of panels produces roughly 975 kWh per year on a south-facing roof. We value self-used electricity at 27.7p and exported surplus at a baseline 10p via SEG. Use the calculator above for your exact tariff.

Unit rate
27.7p/kWh
Standing charge
70.0p/day
Sunshine yield (south)
975 kWh/kW
Export price (baseline)
10p/kWh

Browse the scenarios below. Each battery size has its own expand — open the one that matches your plan (or just explore). For each system size (2–8 kW) we show annual output, how much you use directly, what gets exported, annual benefit, upfront cost, break-even, and a 20-year net. Negative numbers are possible — that’s the honest trade-off when adding more battery than your usage profile justifies.

No battery 5 kW example → Annual benefit: £833, Upfront: £10,173, Break-even: 12.2 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1951 kWh 780 kWh 1170 kWh £216 £117 £333 £4,069 12.2 yrs £2,597
3 kW 2926 kWh 1170 kWh 1756 kWh £324 £176 £500 £6,104 12.2 yrs £3,896
4 kW 3901 kWh 1560 kWh 2341 kWh £433 £234 £667 £8,138 12.2 yrs £5,195
5 kW 4876 kWh 1951 kWh 2926 kWh £541 £293 £833 £10,173 12.2 yrs £6,493
6 kW 5852 kWh 2341 kWh 3511 kWh £649 £351 £1,000 £12,207 12.2 yrs £7,792
7 kW 6827 kWh 2731 kWh 4096 kWh £757 £410 £1,167 £14,242 12.2 yrs £9,091
8 kW 7802 kWh 3121 kWh 4681 kWh £865 £468 £1,333 £16,276 12.2 yrs £10,389

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

3 kWh battery 5 kW example → Annual benefit: £1,006, Upfront: £12,273, Break-even: 12.2 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1951 kWh 1170 kWh 780 kWh £324 £78 £402 £6,169 15.3 yrs £1,880
3 kW 2926 kWh 1756 kWh 1170 kWh £487 £117 £604 £8,204 13.6 yrs £3,870
4 kW 3901 kWh 2341 kWh 1560 kWh £649 £156 £805 £10,238 12.7 yrs £5,860
5 kW 4876 kWh 2926 kWh 1951 kWh £811 £195 £1,006 £12,273 12.2 yrs £7,850
6 kW 5852 kWh 3511 kWh 2341 kWh £973 £234 £1,207 £14,307 11.9 yrs £9,840
7 kW 6827 kWh 4096 kWh 2731 kWh £1,135 £273 £1,409 £16,342 11.6 yrs £11,830
8 kW 7802 kWh 4681 kWh 3121 kWh £1,298 £312 £1,610 £18,376 11.4 yrs £13,820

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

5 kWh battery 5 kW example → Annual benefit: £1,093, Upfront: £13,673, Break-even: 12.5 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1951 kWh 1365 kWh 585 kWh £378 £59 £437 £7,569 17.3 yrs £1,171
3 kW 2926 kWh 2048 kWh 878 kWh £568 £88 £656 £9,604 14.7 yrs £3,507
4 kW 3901 kWh 2731 kWh 1170 kWh £757 £117 £874 £11,638 13.3 yrs £5,842
5 kW 4876 kWh 3414 kWh 1463 kWh £946 £146 £1,093 £13,673 12.5 yrs £8,178
6 kW 5852 kWh 4096 kWh 1756 kWh £1,135 £176 £1,311 £15,707 12.0 yrs £10,514
7 kW 6827 kWh 4779 kWh 2048 kWh £1,325 £205 £1,530 £17,742 11.6 yrs £12,849
8 kW 7802 kWh 5462 kWh 2341 kWh £1,514 £234 £1,748 £19,776 11.3 yrs £15,185

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

7.5 kWh battery 5 kW example → Annual benefit: £1,118, Upfront: £15,423, Break-even: 13.8 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1951 kWh 1424 kWh 527 kWh £395 £53 £447 £9,319 20.8 yrs £-371
3 kW 2926 kWh 2136 kWh 790 kWh £592 £79 £671 £11,354 16.9 yrs £2,068
4 kW 3901 kWh 2848 kWh 1053 kWh £789 £105 £895 £13,388 15.0 yrs £4,507
5 kW 4876 kWh 3560 kWh 1317 kWh £987 £132 £1,118 £15,423 13.8 yrs £6,947
6 kW 5852 kWh 4272 kWh 1580 kWh £1,184 £158 £1,342 £17,457 13.0 yrs £9,386
7 kW 6827 kWh 4984 kWh 1843 kWh £1,382 £184 £1,566 £19,492 12.4 yrs £11,825
8 kW 7802 kWh 5696 kWh 2107 kWh £1,579 £211 £1,790 £21,526 12.0 yrs £14,264

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

10 kWh battery 5 kW example → Annual benefit: £1,136, Upfront: £17,173, Break-even: 15.1 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1951 kWh 1463 kWh 488 kWh £406 £49 £454 £11,069 24.4 yrs £-1,983
3 kW 2926 kWh 2194 kWh 731 kWh £608 £73 £681 £13,104 19.2 yrs £525
4 kW 3901 kWh 2926 kWh 975 kWh £811 £98 £909 £15,138 16.7 yrs £3,034
5 kW 4876 kWh 3657 kWh 1219 kWh £1,014 £122 £1,136 £17,173 15.1 yrs £5,542
6 kW 5852 kWh 4389 kWh 1463 kWh £1,217 £146 £1,363 £19,207 14.1 yrs £8,051
7 kW 6827 kWh 5120 kWh 1707 kWh £1,419 £171 £1,590 £21,242 13.4 yrs £10,559
8 kW 7802 kWh 5852 kWh 1951 kWh £1,622 £195 £1,817 £23,276 12.8 yrs £13,067

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

13.5 kWh battery 5 kW example → Annual benefit: £1,153, Upfront: £19,623, Break-even: 17.0 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1951 kWh 1502 kWh 449 kWh £416 £45 £461 £13,519 29.3 yrs £-4,295
3 kW 2926 kWh 2253 kWh 673 kWh £625 £67 £692 £15,554 22.5 yrs £-1,717
4 kW 3901 kWh 3004 kWh 897 kWh £833 £90 £922 £17,588 19.1 yrs £860
5 kW 4876 kWh 3755 kWh 1122 kWh £1,041 £112 £1,153 £19,623 17.0 yrs £3,438
6 kW 5852 kWh 4506 kWh 1346 kWh £1,249 £135 £1,384 £21,657 15.7 yrs £6,015
7 kW 6827 kWh 5257 kWh 1570 kWh £1,457 £157 £1,614 £23,692 14.7 yrs £8,593
8 kW 7802 kWh 6008 kWh 1795 kWh £1,665 £179 £1,845 £25,726 13.9 yrs £11,171

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

Figures are illustrative and use the same method as the calculator above. For exact results, adjust your roof direction, tariff, and usage in the calculator.

Your Area at a Glance

Your Electricity Rate
27.72p/kWh
Daily Fixed Charge
69.95p/day
Local Sunshine
975kWh/kW
A 1 kW system generates ~975 kWh per year. A typical home uses ~2,700 kWh per year.
Typical System Size
6.0kW
For houses & bungalows in this area

Local Property Data

Property Types

Houses: 63% • Flats: 31% • Bungalows: 6% Based on 14,312 properties

Coverage

Sefton (97%)|West Lancashire (3%)

Areas Covered

Kew, Duke's, Ainsdale, Birkdale, Norwood, Rural West, Cambridge, Harington

Data Sources & Assumptions

Solar yield: PVGIS (EU Joint Research Centre), January 2025 data

Electricity rates: Ofgem price cap, Q4 2025

Installation costs: MCS certified installer data, March 2025

Property data: EPC open data (Open Government Licence), aggregated

All estimates are typical values. Actual results vary based on your specific situation, roof characteristics, and usage patterns.