Solar explained to clever people by people who are not trying to be clever
Home Regions
Insights
Big Roof Britain Solar Payback Index Standing Charge Drag

Solar Panels in SW15 (Wandsworth)

See if solar pays off for you in Wandsworth — 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
12.6 years
After this, it's pure profit
Upfront Cost
£6,104
What you pay to get started
Annual Benefit
£485
What you save every year
Profit Over 25 Years
£6,025
After paying itself off, you're this much ahead

Ready to Get Started?

Get your free quote from Blue Ape Renewables. They'll connect you with MCS-certified installers in your area and handle all the paperwork.

Get Solar Quote →
4.8★ Trustpilot • Octopus Energy trusted partner • MCS certified • No obligation
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

In London, the current unit rate is 25.63p/kWh with a 46.06p/day standing charge. Your postcode’s south-facing sunshine yield is 995 kWh/kW — 4 above the regional median (991).

Read the full story

A typical roof here lands around 3.0 kW, with most eligible homes comfortably fitting within 3–6 kW. Each kilowatt of panels produces roughly 995 kWh per year on a south-facing roof. We value self-used electricity at 25.6p and exported surplus at a baseline 10p via SEG. Use the calculator above for your exact tariff.

Unit rate
25.6p/kWh
Standing charge
46.1p/day
Sunshine yield (south)
995 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: £809, Upfront: £10,173, Break-even: 12.6 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1990 kWh 796 kWh 1194 kWh £204 £119 £323 £4,069 12.6 yrs £2,400
3 kW 2985 kWh 1194 kWh 1791 kWh £306 £179 £485 £6,104 12.6 yrs £3,599
4 kW 3980 kWh 1592 kWh 2388 kWh £408 £239 £647 £8,138 12.6 yrs £4,799
5 kW 4975 kWh 1990 kWh 2985 kWh £510 £299 £809 £10,173 12.6 yrs £5,999
6 kW 5970 kWh 2388 kWh 3582 kWh £612 £358 £970 £12,207 12.6 yrs £7,199
7 kW 6965 kWh 2786 kWh 4179 kWh £714 £418 £1,132 £14,242 12.6 yrs £8,399
8 kW 7960 kWh 3184 kWh 4776 kWh £816 £478 £1,294 £16,276 12.6 yrs £9,599

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: £964, Upfront: £12,273, Break-even: 12.7 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1990 kWh 1194 kWh 796 kWh £306 £80 £386 £6,169 16.0 yrs £1,544
3 kW 2985 kWh 1791 kWh 1194 kWh £459 £119 £578 £8,204 14.2 yrs £3,366
4 kW 3980 kWh 2388 kWh 1592 kWh £612 £159 £771 £10,238 13.3 yrs £5,188
5 kW 4975 kWh 2985 kWh 1990 kWh £765 £199 £964 £12,273 12.7 yrs £7,010
6 kW 5970 kWh 3582 kWh 2388 kWh £918 £239 £1,157 £14,307 12.4 yrs £8,832
7 kW 6965 kWh 4179 kWh 2786 kWh £1,071 £279 £1,350 £16,342 12.1 yrs £10,654
8 kW 7960 kWh 4776 kWh 3184 kWh £1,224 £318 £1,543 £18,376 11.9 yrs £12,476

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: £1,042, Upfront: £13,673, Break-even: 13.1 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1990 kWh 1393 kWh 597 kWh £357 £60 £417 £7,569 18.2 yrs £766
3 kW 2985 kWh 2090 kWh 896 kWh £536 £90 £625 £9,604 15.4 yrs £2,899
4 kW 3980 kWh 2786 kWh 1194 kWh £714 £119 £834 £11,638 14.0 yrs £5,032
5 kW 4975 kWh 3483 kWh 1493 kWh £893 £149 £1,042 £13,673 13.1 yrs £7,165
6 kW 5970 kWh 4179 kWh 1791 kWh £1,071 £179 £1,250 £15,707 12.6 yrs £9,298
7 kW 6965 kWh 4876 kWh 2090 kWh £1,250 £209 £1,459 £17,742 12.2 yrs £11,431
8 kW 7960 kWh 5572 kWh 2388 kWh £1,428 £239 £1,667 £19,776 11.9 yrs £13,564

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: £1,065, Upfront: £15,423, Break-even: 14.5 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1990 kWh 1453 kWh 537 kWh £372 £54 £426 £9,319 21.9 yrs £-797
3 kW 2985 kWh 2179 kWh 806 kWh £559 £81 £639 £11,354 17.8 yrs £1,429
4 kW 3980 kWh 2906 kWh 1075 kWh £745 £107 £852 £13,388 15.7 yrs £3,655
5 kW 4975 kWh 3632 kWh 1343 kWh £931 £134 £1,065 £15,423 14.5 yrs £5,882
6 kW 5970 kWh 4358 kWh 1612 kWh £1,117 £161 £1,278 £17,457 13.7 yrs £8,108
7 kW 6965 kWh 5085 kWh 1881 kWh £1,303 £188 £1,491 £19,492 13.1 yrs £10,334
8 kW 7960 kWh 5811 kWh 2149 kWh £1,489 £215 £1,704 £21,526 12.6 yrs £12,561

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: £1,081, Upfront: £17,173, Break-even: 15.9 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1990 kWh 1493 kWh 498 kWh £383 £50 £432 £11,069 25.6 yrs £-2,423
3 kW 2985 kWh 2239 kWh 746 kWh £574 £75 £648 £13,104 20.2 yrs £-134
4 kW 3980 kWh 2985 kWh 995 kWh £765 £100 £865 £15,138 17.5 yrs £2,154
5 kW 4975 kWh 3731 kWh 1244 kWh £956 £124 £1,081 £17,173 15.9 yrs £4,443
6 kW 5970 kWh 4478 kWh 1493 kWh £1,148 £149 £1,297 £19,207 14.8 yrs £6,731
7 kW 6965 kWh 5224 kWh 1741 kWh £1,339 £174 £1,513 £21,242 14.0 yrs £9,020
8 kW 7960 kWh 5970 kWh 1990 kWh £1,530 £199 £1,729 £23,276 13.5 yrs £11,308

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: £1,096, Upfront: £19,623, Break-even: 17.9 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1990 kWh 1532 kWh 458 kWh £393 £46 £439 £13,519 30.8 yrs £-4,749
3 kW 2985 kWh 2299 kWh 687 kWh £589 £69 £658 £15,554 23.6 yrs £-2,398
4 kW 3980 kWh 3065 kWh 915 kWh £786 £92 £877 £17,588 20.1 yrs £-47
5 kW 4975 kWh 3831 kWh 1144 kWh £982 £114 £1,096 £19,623 17.9 yrs £2,304
6 kW 5970 kWh 4597 kWh 1373 kWh £1,178 £137 £1,316 £21,657 16.5 yrs £4,654
7 kW 6965 kWh 5363 kWh 1602 kWh £1,375 £160 £1,535 £23,692 15.4 yrs £7,005
8 kW 7960 kWh 6130 kWh 1831 kWh £1,571 £183 £1,754 £25,726 14.7 yrs £9,356

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.

Insights for SW15

Figures below are tailored to SW15 — click through for full league tables.

Big-Roof Britain Rank #1928 of 2182
4.2 kWp (UK avg 5.1 kWp)
~9 panels (≈430 W)
Solar Payback Index Rank #1285 of 2997
11.0 years (UK avg 11.3 years)
~£1,110 /yr • £12,207 upfront
Standing-Charge Drag Rank #280 of 2997
15.1% (UK avg 21.7%) drag on savings
£168 fixed • ~£1,110 /yr value

Your Area at a Glance

Your Electricity Rate
25.63p/kWh
Daily Fixed Charge
46.06p/day
Local Sunshine
995kWh/kW
A 1 kW system generates ~995 kWh per year. A typical home uses ~2,700 kWh per year.
Typical System Size
3.0kW
For eligible homes in this area

⚠️ This area is predominantly flats. Many residents require freeholder approval for solar installations. System size shown reflects houses and bungalows only.

Local Property Data

Property Types

Houses: 24% • Flats: 67% • Bungalows: 1% Based on 18,400 properties

Coverage

Wandsworth (97%)|Kingston upon Thames (2%)|Richmond upon Thames (1%)

Areas Covered

West Putney, Roehampton, Thamesfield, East Putney, Coombe Hill, Mortlake & Barnes Common, West Hill, East Sheen

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.

Compare nearby areas

Nearby in London

SW18 (Wandsworth)
≈2.3 km away
Local sunshine: ~992 kWh/kWp · -0% vs SW15
SW13 (Richmond upon Thames)
≈2.4 km away
Local sunshine: ~995 kWh/kWp · -0% vs SW15
SW6 (Hammersmith and Fulham)
≈2.5 km away
Local sunshine: ~992 kWh/kWp · -0% vs SW15
SW14 (Richmond upon Thames)
≈3.4 km away
Local sunshine: ~994 kWh/kWp · -0% vs SW15
SW10 (Kensington and Chelsea)
≈3.7 km away
Local sunshine: ~992 kWh/kWp · -0% vs SW15
W6 (Hammersmith and Fulham)
≈3.7 km away
Local sunshine: ~995 kWh/kWp · +0% vs SW15

Similar sunshine across the UK

MK16 (Milton Keynes)
~995 kWh/kWp · +0% vs SW15
NG31 (South Kesteven)
~995 kWh/kWp · +0% vs SW15
SM3 (Sutton)
~995 kWh/kWp · -0% vs SW15