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Solar panel cost in Merton (CR4)

See realistic solar installation costs, savings and payback for CR4 (Merton) 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
9.9 years
After this, it's pure profit
Upfront Cost
£8,139
What you pay to get started
Annual Benefit
£821
What you save every year
Profit Over 25 Years
£12,383
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 993 kWh/kW — 2 above the regional median (991).

Read the full story

A typical roof here lands around 5.0 kW, with most eligible homes comfortably fitting within 3–6 kW. Each kilowatt of panels produces roughly 993 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)
993 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: £821, Upfront: £8,139, Break-even: 9.9 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1985 kWh 794 kWh 1191 kWh £209 £119 £328 £3,256 9.9 yrs £3,312
3 kW 2978 kWh 1191 kWh 1787 kWh £314 £179 £493 £4,883 9.9 yrs £4,967
4 kW 3970 kWh 1588 kWh 2382 kWh £418 £238 £657 £6,511 9.9 yrs £6,623
5 kW 4963 kWh 1985 kWh 2978 kWh £523 £298 £821 £8,139 9.9 yrs £8,279
6 kW 5956 kWh 2382 kWh 3573 kWh £628 £357 £985 £9,767 9.9 yrs £9,935
7 kW 6948 kWh 2779 kWh 4169 kWh £732 £417 £1,149 £11,394 9.9 yrs £11,591
8 kW 7941 kWh 3176 kWh 4765 kWh £837 £476 £1,313 £13,022 9.9 yrs £13,246

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,628, battery £/kWh = 700.

3 kWh battery 5 kW example → Annual benefit: £983, Upfront: £10,239, Break-even: 10.4 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1985 kWh 1191 kWh 794 kWh £314 £79 £393 £5,356 13.6 yrs £2,510
3 kW 2978 kWh 1787 kWh 1191 kWh £471 £119 £590 £6,983 11.8 yrs £4,815
4 kW 3970 kWh 2382 kWh 1588 kWh £628 £159 £787 £8,611 10.9 yrs £7,120
5 kW 4963 kWh 2978 kWh 1985 kWh £785 £199 £983 £10,239 10.4 yrs £9,425
6 kW 5956 kWh 3573 kWh 2382 kWh £942 £238 £1,180 £11,867 10.1 yrs £11,730
7 kW 6948 kWh 4169 kWh 2779 kWh £1,099 £278 £1,376 £13,494 9.8 yrs £14,035
8 kW 7941 kWh 4765 kWh 3176 kWh £1,255 £318 £1,573 £15,122 9.6 yrs £16,340

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,628, battery £/kWh = 700.

5 kWh battery 5 kW example → Annual benefit: £1,064, Upfront: £11,639, Break-even: 10.9 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1985 kWh 1390 kWh 596 kWh £366 £60 £426 £6,756 15.9 yrs £1,759
3 kW 2978 kWh 2084 kWh 893 kWh £549 £89 £639 £8,383 13.1 yrs £4,389
4 kW 3970 kWh 2779 kWh 1191 kWh £732 £119 £851 £10,011 11.8 yrs £7,018
5 kW 4963 kWh 3474 kWh 1489 kWh £915 £149 £1,064 £11,639 10.9 yrs £9,648
6 kW 5956 kWh 4169 kWh 1787 kWh £1,099 £179 £1,277 £13,267 10.4 yrs £12,277
7 kW 6948 kWh 4864 kWh 2084 kWh £1,282 £208 £1,490 £14,894 10.0 yrs £14,907
8 kW 7941 kWh 5559 kWh 2382 kWh £1,465 £238 £1,703 £16,522 9.7 yrs £17,536

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,628, battery £/kWh = 700.

7.5 kWh battery 5 kW example → Annual benefit: £1,089, Upfront: £13,389, Break-even: 12.3 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1985 kWh 1449 kWh 536 kWh £382 £54 £435 £8,506 19.5 yrs £204
3 kW 2978 kWh 2174 kWh 804 kWh £573 £80 £653 £10,133 15.5 yrs £2,931
4 kW 3970 kWh 2898 kWh 1072 kWh £764 £107 £871 £11,761 13.5 yrs £5,658
5 kW 4963 kWh 3623 kWh 1340 kWh £955 £134 £1,089 £13,389 12.3 yrs £8,385
6 kW 5956 kWh 4348 kWh 1608 kWh £1,146 £161 £1,306 £15,017 11.5 yrs £11,112
7 kW 6948 kWh 5072 kWh 1876 kWh £1,337 £188 £1,524 £16,644 10.9 yrs £13,838
8 kW 7941 kWh 5797 kWh 2144 kWh £1,527 £214 £1,742 £18,272 10.5 yrs £16,565

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,628, battery £/kWh = 700.

10 kWh battery 5 kW example → Annual benefit: £1,105, Upfront: £15,139, Break-even: 13.7 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1985 kWh 1489 kWh 496 kWh £392 £50 £442 £10,256 23.2 yrs £-1,416
3 kW 2978 kWh 2233 kWh 744 kWh £588 £74 £663 £11,883 17.9 yrs £1,376
4 kW 3970 kWh 2978 kWh 993 kWh £785 £99 £884 £13,511 15.3 yrs £4,167
5 kW 4963 kWh 3722 kWh 1241 kWh £981 £124 £1,105 £15,139 13.7 yrs £6,959
6 kW 5956 kWh 4467 kWh 1489 kWh £1,177 £149 £1,326 £16,767 12.6 yrs £9,751
7 kW 6948 kWh 5211 kWh 1737 kWh £1,373 £174 £1,547 £18,394 11.9 yrs £12,543
8 kW 7941 kWh 5956 kWh 1985 kWh £1,569 £199 £1,768 £20,022 11.3 yrs £15,335

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,628, battery £/kWh = 700.

13.5 kWh battery 5 kW example → Annual benefit: £1,121, Upfront: £17,589, Break-even: 15.7 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1985 kWh 1529 kWh 457 kWh £403 £46 £448 £12,706 28.3 yrs £-3,736
3 kW 2978 kWh 2293 kWh 685 kWh £604 £68 £673 £14,333 21.3 yrs £-880
4 kW 3970 kWh 3057 kWh 913 kWh £806 £91 £897 £15,961 17.8 yrs £1,977
5 kW 4963 kWh 3822 kWh 1142 kWh £1,007 £114 £1,121 £17,589 15.7 yrs £4,834
6 kW 5956 kWh 4586 kWh 1370 kWh £1,208 £137 £1,345 £19,217 14.3 yrs £7,691
7 kW 6948 kWh 5350 kWh 1598 kWh £1,410 £160 £1,570 £20,844 13.3 yrs £10,547
8 kW 7941 kWh 6114 kWh 1826 kWh £1,611 £183 £1,794 £22,472 12.5 yrs £13,404

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,628, 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 Merton

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 CR4

Figures below are tailored to CR4 — click through for full league tables.

Big-Roof Britain Rank #2019 of 2182
4.1 kWp (UK avg 5.1 kWp)
~9 panels (≈430 W)
Solar Payback Index Rank #784 of 2996
9.9 years (UK avg 10.8 years)
~£821 /yr • £8,139 upfront
Standing-Charge Drag Rank #497 of 2996
19.9% (UK avg 26.6%) drag on savings
£163 fixed • ~£821 /yr value
Aspect Penalty View ranking →
East −21.6% West −19.4%
Typical output loss versus a south-facing roof (lower is better)

Seasonal solar output in CR4

Monthly generation per kilowatt of solar panels

kWh 39 Jan 51 Feb 84 Mar 111 Apr 118 May 120 Jun 121 Jul 108 Aug 93 Sep 67 Oct 46 Nov 35 Dec
Best month Worst month Winter (Dec–Feb) Other months

Winter output: 50.4% 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 167 kWh in winter, or 331 kWh in an average month.

Your Area at a Glance

Your Electricity Rate
26.35p/kWh
Daily Fixed Charge
44.78p/day
Local Sunshine
993kWh/kW
A 1 kW system generates ~993 kWh per year. A typical home uses ~2,700 kWh per year.
Typical System Size
5.0kW
For houses & bungalows in this area

Local Property Data

Property Types

Houses: 49% • Flats: 44% • Bungalows: 1% Based on 15,496 properties

Coverage

Merton (66%)|Croydon (31%)|Sutton (2%)

Areas Covered

Cricket Green, West Thornton, Thornton Heath, Bensham Manor, Figge's Marsh, Pollards Hill, Graveney, Lavender Fields + 4 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

SW17 (Wandsworth)
≈2.8 km away
Local sunshine: ~996 kWh/kWp · +0% vs CR4
SW16 (Lambeth)
≈3.2 km away
Local sunshine: ~993 kWh/kWp · +0% vs CR4
SM4 (Merton)
≈3.2 km away
Local sunshine: ~999 kWh/kWp · +1% vs CR4
SW19 (Merton)
≈4.2 km away
Local sunshine: ~996 kWh/kWp · +0% vs CR4
SW20 (Merton)
≈4.7 km away
Local sunshine: ~996 kWh/kWp · +0% vs CR4
SW12 (Wandsworth)
≈4.7 km away
Local sunshine: ~993 kWh/kWp · +0% vs CR4

Similar sunshine across the UK

GU11 (Rushmoor)
~993 kWh/kWp · -0% vs CR4
HA5 (Harrow)
~993 kWh/kWp · -0% vs CR4
AL1 (St Albans)
~993 kWh/kWp · -0% vs CR4