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Solar panel cost in Lambeth (SW2)

See realistic solar installation costs, savings and payback for SW2 (Lambeth) in under a minute using official UK data. Start with the calculator, then get a no-obligation quote from an MCS-certified installer. You can also ask the SolarByPostcode assistant to sanity-check your roof, bills and plans.

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
11.2 years
After this, it's pure profit
Upfront Cost
£5,481
What you pay to get started
Annual Benefit
£491
What you save every year
Profit Over 25 Years
£6,805
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: The official cost per kW is lower above 4 kW, so a 5–6 kW system can pay back a little faster than a 3–4 kW system on otherwise identical assumptions.
  • 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

Panel costs: Uses March 2026 TIC mean installation costs: £1,827/kW up to 4 kW and £1,628/kW above 4 kW.

Other costs: Battery prices are modelled at £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 26.35p/kWh with a 44.78p/day standing charge. Your postcode’s south-facing sunshine yield is 990 kWh/kW — 0 below 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 990 kWh per year on a south-facing roof. We value self-used electricity at 26.4p and exported surplus at a baseline 10p via SEG. Use the calculator above for your exact tariff.

Unit rate
26.4p/kWh
Standing charge
44.8p/day
Sunshine yield (south)
990 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: £819, Upfront: £9,134, Break-even: 11.2 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1981 kWh 792 kWh 1188 kWh £209 £119 £328 £3,654 11.2 yrs £2,899
3 kW 2971 kWh 1188 kWh 1783 kWh £313 £178 £491 £5,481 11.2 yrs £4,348
4 kW 3962 kWh 1585 kWh 2377 kWh £418 £238 £655 £7,307 11.2 yrs £5,797
5 kW 4952 kWh 1981 kWh 2971 kWh £522 £297 £819 £9,134 11.2 yrs £7,247
6 kW 5942 kWh 2377 kWh 3565 kWh £626 £357 £983 £10,961 11.2 yrs £8,696
7 kW 6933 kWh 2773 kWh 4160 kWh £731 £416 £1,147 £12,788 11.2 yrs £10,145
8 kW 7923 kWh 3169 kWh 4754 kWh £835 £475 £1,310 £14,615 11.2 yrs £11,595

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,827, battery £/kWh = 700.

3 kWh battery 5 kW example → Annual benefit: £981, Upfront: £11,234, Break-even: 11.5 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1981 kWh 1188 kWh 792 kWh £313 £79 £392 £5,754 14.7 yrs £2,094
3 kW 2971 kWh 1783 kWh 1188 kWh £470 £119 £589 £7,581 12.9 yrs £4,191
4 kW 3962 kWh 2377 kWh 1585 kWh £626 £158 £785 £9,407 12.0 yrs £6,288
5 kW 4952 kWh 2971 kWh 1981 kWh £783 £198 £981 £11,234 11.5 yrs £8,385
6 kW 5942 kWh 3565 kWh 2377 kWh £939 £238 £1,177 £13,061 11.1 yrs £10,482
7 kW 6933 kWh 4160 kWh 2773 kWh £1,096 £277 £1,373 £14,888 10.8 yrs £12,579
8 kW 7923 kWh 4754 kWh 3169 kWh £1,253 £317 £1,570 £16,715 10.6 yrs £14,676

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,827, battery £/kWh = 700.

5 kWh battery 5 kW example → Annual benefit: £1,062, Upfront: £12,634, Break-even: 11.9 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1981 kWh 1387 kWh 594 kWh £365 £59 £425 £7,154 16.8 yrs £1,342
3 kW 2971 kWh 2080 kWh 891 kWh £548 £89 £637 £8,981 14.1 yrs £3,763
4 kW 3962 kWh 2773 kWh 1188 kWh £731 £119 £850 £10,807 12.7 yrs £6,184
5 kW 4952 kWh 3466 kWh 1486 kWh £913 £149 £1,062 £12,634 11.9 yrs £8,604
6 kW 5942 kWh 4160 kWh 1783 kWh £1,096 £178 £1,274 £14,461 11.3 yrs £11,025
7 kW 6933 kWh 4853 kWh 2080 kWh £1,279 £208 £1,487 £16,288 11.0 yrs £13,446
8 kW 7923 kWh 5546 kWh 2377 kWh £1,461 £238 £1,699 £18,115 10.7 yrs £15,867

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,827, battery £/kWh = 700.

7.5 kWh battery 5 kW example → Annual benefit: £1,086, Upfront: £14,384, Break-even: 13.2 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1981 kWh 1446 kWh 535 kWh £381 £53 £434 £8,904 20.5 yrs £-214
3 kW 2971 kWh 2169 kWh 802 kWh £572 £80 £652 £10,731 16.5 yrs £2,304
4 kW 3962 kWh 2892 kWh 1070 kWh £762 £107 £869 £12,557 14.5 yrs £4,822
5 kW 4952 kWh 3615 kWh 1337 kWh £953 £134 £1,086 £14,384 13.2 yrs £7,340
6 kW 5942 kWh 4338 kWh 1604 kWh £1,143 £160 £1,303 £16,211 12.4 yrs £9,858
7 kW 6933 kWh 5061 kWh 1872 kWh £1,334 £187 £1,521 £18,038 11.9 yrs £12,376
8 kW 7923 kWh 5784 kWh 2139 kWh £1,524 £214 £1,738 £19,865 11.4 yrs £14,894

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,827, battery £/kWh = 700.

10 kWh battery 5 kW example → Annual benefit: £1,102, Upfront: £16,134, Break-even: 14.6 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1981 kWh 1486 kWh 495 kWh £391 £50 £441 £10,654 24.2 yrs £-1,834
3 kW 2971 kWh 2228 kWh 743 kWh £587 £74 £661 £12,481 18.9 yrs £748
4 kW 3962 kWh 2971 kWh 990 kWh £783 £99 £882 £14,307 16.2 yrs £3,331
5 kW 4952 kWh 3714 kWh 1238 kWh £979 £124 £1,102 £16,134 14.6 yrs £5,914
6 kW 5942 kWh 4457 kWh 1486 kWh £1,174 £149 £1,323 £17,961 13.6 yrs £8,497
7 kW 6933 kWh 5199 kWh 1733 kWh £1,370 £173 £1,543 £19,788 12.8 yrs £11,080
8 kW 7923 kWh 5942 kWh 1981 kWh £1,566 £198 £1,764 £21,615 12.3 yrs £13,663

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,827, battery £/kWh = 700.

13.5 kWh battery 5 kW example → Annual benefit: £1,119, Upfront: £18,584, Break-even: 16.6 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1981 kWh 1525 kWh 456 kWh £402 £46 £447 £13,104 29.3 yrs £-4,155
3 kW 2971 kWh 2288 kWh 683 kWh £603 £68 £671 £14,931 22.2 yrs £-1,507
4 kW 3962 kWh 3050 kWh 911 kWh £804 £91 £895 £16,757 18.7 yrs £1,140
5 kW 4952 kWh 3813 kWh 1139 kWh £1,005 £114 £1,119 £18,584 16.6 yrs £3,788
6 kW 5942 kWh 4576 kWh 1367 kWh £1,206 £137 £1,342 £20,411 15.2 yrs £6,436
7 kW 6933 kWh 5338 kWh 1595 kWh £1,407 £159 £1,566 £22,238 14.2 yrs £9,083
8 kW 7923 kWh 6101 kWh 1822 kWh £1,608 £182 £1,790 £24,065 13.4 yrs £11,731

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,827, 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.

Before you request quotes in Lambeth

Use the numbers above to sanity-check installer quotes. The main things to compare are system size, battery assumptions, payback claims, MCS certification, DNO paperwork and export assumptions.

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Understand DNO, G98 and G99 export limits

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Insights for SW2

Figures below are tailored to SW2 — click through for full league tables.

Big-Roof Britain Rank #2138 of 2182
3.7 kWp (UK avg 5.1 kWp)
~8 panels (≈430 W)
Solar Payback Index Rank #990 of 2996
9.9 years (UK avg 10.8 years)
~£982 /yr • £9,767 upfront
Standing-Charge Drag Rank #103 of 2996
16.6% (UK avg 26.6%) drag on savings
£163 fixed • ~£982 /yr value
Aspect Penalty View ranking →
East −22.0% West −19.4%
Typical output loss versus a south-facing roof (lower is better)

Seasonal solar output in SW2

Monthly generation per kilowatt of solar panels

kWh 40 Jan 51 Feb 84 Mar 111 Apr 117 May 119 Jun 120 Jul 107 Aug 93 Sep 67 Oct 47 Nov 35 Dec
Best month Worst month Winter (Dec–Feb) Other months

Winter output: 51.0% of an average month (Dec–Feb)

Best / worst month: Jul / Dec

These figures show output per kilowatt (kW) of panels installed. In winter, a 1 kW system here produces about 42 kWh per month; the average month produces around 83 kWh. So a typical 4 kW home system would generate roughly 168 kWh in winter, or 330 kWh in an average month.

Your Area at a Glance

Your Electricity Rate
26.35p/kWh
Daily Fixed Charge
44.78p/day
Local Sunshine
990kWh/kW
A 1 kW system generates ~990 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: 18% • Flats: 73% • Bungalows: 0% Based on 18,126 properties

Coverage

Lambeth (100%)

Areas Covered

Brixton Acre Lane, Brixton Rush Common, Streatham Hill East, St Martin's, Clapham Park, Streatham Hill West & Thornton, Brixton Windrush, Herne Hill & Loughborough Junction + 3 more

Data Sources & Assumptions

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

Electricity rates: Ofgem price cap, Q3 2026

Installation costs: DESNZ/MCS data, March 2026 (TIC)

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

SE24 (Lambeth)
≈1.4 km away
Local sunshine: ~993 kWh/kWp · +0% vs SW2
SW4 (Lambeth)
≈1.5 km away
Local sunshine: ~990 kWh/kWp · +0% vs SW2
SW9 (Lambeth)
≈1.7 km away
Local sunshine: ~991 kWh/kWp · +0% vs SW2
SW99 (Lambeth)
≈2.1 km away
Local sunshine: ~991 kWh/kWp · +0% vs SW2
SW12 (Wandsworth)
≈2.2 km away
Local sunshine: ~993 kWh/kWp · +0% vs SW2
SW8 (Lambeth)
≈2.5 km away
Local sunshine: ~991 kWh/kWp · +0% vs SW2

Similar sunshine across the UK

N13 (Enfield)
~990 kWh/kWp · +0% vs SW2
LE16 (Harborough)
~990 kWh/kWp · +0% vs SW2
LE94 (Harborough)
~990 kWh/kWp · +0% vs SW2