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Solar panel cost in Windsor and Maidenhead (SL5)

See realistic solar installation costs, savings and payback for SL5 (Windsor and Maidenhead) 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
£9,767
What you pay to get started
Annual Benefit
£986
What you save every year
Profit Over 25 Years
£14,871
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 Southern, the current unit rate is 26.42p/kWh with a 49.70p/day standing charge. Your postcode’s south-facing sunshine yield is 991 kWh/kW — 10 below the regional median (1001).

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 991 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
49.7p/day
Sunshine yield (south)
991 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 1983 kWh 793 kWh 1190 kWh £210 £119 £329 £3,256 9.9 yrs £3,315
3 kW 2974 kWh 1190 kWh 1785 kWh £314 £178 £493 £4,883 9.9 yrs £4,972
4 kW 3966 kWh 1586 kWh 2379 kWh £419 £238 £657 £6,511 9.9 yrs £6,629
5 kW 4957 kWh 1983 kWh 2974 kWh £524 £297 £821 £8,139 9.9 yrs £8,287
6 kW 5948 kWh 2379 kWh 3569 kWh £629 £357 £986 £9,767 9.9 yrs £9,944
7 kW 6940 kWh 2776 kWh 4164 kWh £733 £416 £1,150 £11,394 9.9 yrs £11,601
8 kW 7931 kWh 3172 kWh 4759 kWh £838 £476 £1,314 £13,022 9.9 yrs £13,258

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: £984, 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 1983 kWh 1190 kWh 793 kWh £314 £79 £394 £5,356 13.6 yrs £2,517
3 kW 2974 kWh 1785 kWh 1190 kWh £471 £119 £590 £6,983 11.8 yrs £4,825
4 kW 3966 kWh 2379 kWh 1586 kWh £629 £159 £787 £8,611 10.9 yrs £7,134
5 kW 4957 kWh 2974 kWh 1983 kWh £786 £198 £984 £10,239 10.4 yrs £9,442
6 kW 5948 kWh 3569 kWh 2379 kWh £943 £238 £1,181 £11,867 10.0 yrs £11,751
7 kW 6940 kWh 4164 kWh 2776 kWh £1,100 £278 £1,378 £13,494 9.8 yrs £14,059
8 kW 7931 kWh 4759 kWh 3172 kWh £1,257 £317 £1,574 £15,122 9.6 yrs £16,368

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: £1,065, 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 1983 kWh 1388 kWh 595 kWh £367 £59 £426 £6,756 15.9 yrs £1,768
3 kW 2974 kWh 2082 kWh 892 kWh £550 £89 £639 £8,383 13.1 yrs £4,402
4 kW 3966 kWh 2776 kWh 1190 kWh £733 £119 £852 £10,011 11.7 yrs £7,036
5 kW 4957 kWh 3470 kWh 1487 kWh £917 £149 £1,065 £11,639 10.9 yrs £9,670
6 kW 5948 kWh 4164 kWh 1785 kWh £1,100 £178 £1,279 £13,267 10.4 yrs £12,304
7 kW 6940 kWh 4858 kWh 2082 kWh £1,283 £208 £1,492 £14,894 10.0 yrs £14,938
8 kW 7931 kWh 5552 kWh 2379 kWh £1,467 £238 £1,705 £16,522 9.7 yrs £17,572

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: £1,090, 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 1983 kWh 1447 kWh 535 kWh £382 £54 £436 £8,506 19.5 yrs £213
3 kW 2974 kWh 2171 kWh 803 kWh £574 £80 £654 £10,133 15.5 yrs £2,945
4 kW 3966 kWh 2895 kWh 1071 kWh £765 £107 £872 £11,761 13.5 yrs £5,677
5 kW 4957 kWh 3619 kWh 1338 kWh £956 £134 £1,090 £13,389 12.3 yrs £8,408
6 kW 5948 kWh 4342 kWh 1606 kWh £1,147 £161 £1,308 £15,017 11.5 yrs £11,140
7 kW 6940 kWh 5066 kWh 1874 kWh £1,338 £187 £1,526 £16,644 10.9 yrs £13,872
8 kW 7931 kWh 5790 kWh 2141 kWh £1,530 £214 £1,744 £18,272 10.5 yrs £16,604

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: £1,106, 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 1983 kWh 1487 kWh 496 kWh £393 £50 £442 £10,256 23.2 yrs £-1,406
3 kW 2974 kWh 2231 kWh 744 kWh £589 £74 £664 £11,883 17.9 yrs £1,390
4 kW 3966 kWh 2974 kWh 991 kWh £786 £99 £885 £13,511 15.3 yrs £4,187
5 kW 4957 kWh 3718 kWh 1239 kWh £982 £124 £1,106 £15,139 13.7 yrs £6,984
6 kW 5948 kWh 4461 kWh 1487 kWh £1,179 £149 £1,327 £16,767 12.6 yrs £9,781
7 kW 6940 kWh 5205 kWh 1735 kWh £1,375 £173 £1,549 £18,394 11.9 yrs £12,578
8 kW 7931 kWh 5948 kWh 1983 kWh £1,572 £198 £1,770 £20,022 11.3 yrs £15,375

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: £1,122, 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 1983 kWh 1527 kWh 456 kWh £403 £46 £449 £12,706 28.3 yrs £-3,726
3 kW 2974 kWh 2290 kWh 684 kWh £605 £68 £673 £14,333 21.3 yrs £-864
4 kW 3966 kWh 3053 kWh 912 kWh £807 £91 £898 £15,961 17.8 yrs £1,998
5 kW 4957 kWh 3817 kWh 1140 kWh £1,008 £114 £1,122 £17,589 15.7 yrs £4,860
6 kW 5948 kWh 4580 kWh 1368 kWh £1,210 £137 £1,347 £19,217 14.3 yrs £7,722
7 kW 6940 kWh 5344 kWh 1596 kWh £1,412 £160 £1,571 £20,844 13.3 yrs £10,583
8 kW 7931 kWh 6107 kWh 1824 kWh £1,613 £182 £1,796 £22,472 12.5 yrs £13,445

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 Windsor and Maidenhead

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 SL5

Figures below are tailored to SL5 — click through for full league tables.

Big-Roof Britain Rank #127 of 2182
6.4 kWp (UK avg 5.1 kWp)
~13 panels (≈430 W)
Solar Payback Index Rank #955 of 2996
9.9 years (UK avg 10.8 years)
~£985 /yr • £9,767 upfront
Standing-Charge Drag Rank #282 of 2996
18.4% (UK avg 26.6%) drag on savings
£181 fixed • ~£985 /yr value
Aspect Penalty View ranking →
East −21.3% West −19.2%
Typical output loss versus a south-facing roof (lower is better)

Seasonal solar output in SL5

Monthly generation per kilowatt of solar panels

kWh 40 Jan 51 Feb 83 Mar 110 Apr 118 May 120 Jun 120 Jul 108 Aug 93 Sep 67 Oct 46 Nov 35 Dec
Best month Worst month Winter (Dec–Feb) Other months

Winter output: 50.6% 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 330 kWh in an average month.

Your Area at a Glance

Your Electricity Rate
26.42p/kWh
Daily Fixed Charge
49.70p/day
Local Sunshine
991kWh/kW
A 1 kW system generates ~991 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: 61% • Flats: 30% • Bungalows: 7% Based on 6,927 properties

Coverage

Windsor and Maidenhead (82%)|Bracknell Forest (17%)|Runnymede (1%)

Areas Covered

Ascot & Sunninghill, Sunningdale & Cheapside, Winkfield & Warfield East, Swinley Forest, Virginia Water, Windlesham & Chobham, Old Windsor, Bagshot

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 Southern

GU20 (Surrey Heath)
≈4.1 km away
Local sunshine: ~996 kWh/kWp · +0% vs SL5
GU19 (Surrey Heath)
≈5.4 km away
Local sunshine: ~992 kWh/kWp · +0% vs SL5
GU18 (Surrey Heath)
≈5.9 km away
Local sunshine: ~992 kWh/kWp · +0% vs SL5
GU25 (Runnymede)
≈6.1 km away
Local sunshine: ~997 kWh/kWp · +1% vs SL5
RG12 (Bracknell Forest)
≈7.0 km away
Local sunshine: ~992 kWh/kWp · +0% vs SL5
GU24 (Surrey Heath)
≈7.5 km away
Local sunshine: ~995 kWh/kWp · +0% vs SL5

Similar sunshine across the UK

HA1 (Harrow)
~991 kWh/kWp · +0% vs SL5
E14 (Tower Hamlets)
~991 kWh/kWp · -0% vs SL5
HA3 (Harrow)
~992 kWh/kWp · +0% vs SL5