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Solar panel cost in Watford (WD24)

See realistic solar installation costs, savings and payback for WD24 (Watford) 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
10.0 years
After this, it's pure profit
Upfront Cost
£8,139
What you pay to get started
Annual Benefit
£815
What you save every year
Profit Over 25 Years
£12,236
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 Eastern, the current unit rate is 26.38p/kWh with a 53.94p/day standing charge. Your postcode’s south-facing sunshine yield is 985 kWh/kW — 24 below the regional median (1009).

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 985 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
53.9p/day
Sunshine yield (south)
985 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: £815, Upfront: £8,139, Break-even: 10.0 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1970 kWh 788 kWh 1182 kWh £208 £118 £326 £3,256 10.0 yrs £3,264
3 kW 2954 kWh 1182 kWh 1773 kWh £312 £177 £489 £4,883 10.0 yrs £4,896
4 kW 3939 kWh 1576 kWh 2363 kWh £416 £236 £652 £6,511 10.0 yrs £6,529
5 kW 4924 kWh 1970 kWh 2954 kWh £520 £295 £815 £8,139 10.0 yrs £8,161
6 kW 5908 kWh 2363 kWh 3545 kWh £623 £355 £978 £9,767 10.0 yrs £9,793
7 kW 6893 kWh 2757 kWh 4136 kWh £727 £414 £1,141 £11,394 10.0 yrs £11,425
8 kW 7878 kWh 3151 kWh 4727 kWh £831 £473 £1,304 £13,022 10.0 yrs £13,057

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: £976, Upfront: £10,239, Break-even: 10.5 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1970 kWh 1182 kWh 788 kWh £312 £79 £391 £5,356 13.7 yrs £2,455
3 kW 2954 kWh 1773 kWh 1182 kWh £468 £118 £586 £6,983 11.9 yrs £4,732
4 kW 3939 kWh 2363 kWh 1576 kWh £623 £158 £781 £8,611 11.0 yrs £7,009
5 kW 4924 kWh 2954 kWh 1970 kWh £779 £197 £976 £10,239 10.5 yrs £9,287
6 kW 5908 kWh 3545 kWh 2363 kWh £935 £236 £1,172 £11,867 10.1 yrs £11,564
7 kW 6893 kWh 4136 kWh 2757 kWh £1,091 £276 £1,367 £13,494 9.9 yrs £13,842
8 kW 7878 kWh 4727 kWh 3151 kWh £1,247 £315 £1,562 £15,122 9.7 yrs £16,119

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: £1,057, Upfront: £11,639, Break-even: 11.0 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1970 kWh 1379 kWh 591 kWh £364 £59 £423 £6,756 16.0 yrs £1,700
3 kW 2954 kWh 2068 kWh 886 kWh £546 £89 £634 £8,383 13.2 yrs £4,300
4 kW 3939 kWh 2757 kWh 1182 kWh £727 £118 £846 £10,011 11.8 yrs £6,900
5 kW 4924 kWh 3447 kWh 1477 kWh £909 £148 £1,057 £11,639 11.0 yrs £9,500
6 kW 5908 kWh 4136 kWh 1773 kWh £1,091 £177 £1,268 £13,267 10.5 yrs £12,100
7 kW 6893 kWh 4825 kWh 2068 kWh £1,273 £207 £1,480 £14,894 10.1 yrs £14,700
8 kW 7878 kWh 5515 kWh 2363 kWh £1,455 £236 £1,691 £16,522 9.8 yrs £17,300

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: £1,081, Upfront: £13,389, Break-even: 12.4 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1970 kWh 1438 kWh 532 kWh £379 £53 £432 £8,506 19.7 yrs £143
3 kW 2954 kWh 2157 kWh 798 kWh £569 £80 £649 £10,133 15.6 yrs £2,840
4 kW 3939 kWh 2875 kWh 1064 kWh £759 £106 £865 £11,761 13.6 yrs £5,537
5 kW 4924 kWh 3594 kWh 1329 kWh £948 £133 £1,081 £13,389 12.4 yrs £8,234
6 kW 5908 kWh 4313 kWh 1595 kWh £1,138 £160 £1,297 £15,017 11.6 yrs £10,930
7 kW 6893 kWh 5032 kWh 1861 kWh £1,327 £186 £1,514 £16,644 11.0 yrs £13,627
8 kW 7878 kWh 5751 kWh 2127 kWh £1,517 £213 £1,730 £18,272 10.6 yrs £16,324

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: £1,097, Upfront: £15,139, 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 1970 kWh 1477 kWh 492 kWh £390 £49 £439 £10,256 23.4 yrs £-1,477
3 kW 2954 kWh 2216 kWh 739 kWh £584 £74 £658 £11,883 18.0 yrs £1,284
4 kW 3939 kWh 2954 kWh 985 kWh £779 £98 £878 £13,511 15.4 yrs £4,045
5 kW 4924 kWh 3693 kWh 1231 kWh £974 £123 £1,097 £15,139 13.8 yrs £6,806
6 kW 5908 kWh 4431 kWh 1477 kWh £1,169 £148 £1,317 £16,767 12.7 yrs £9,568
7 kW 6893 kWh 5170 kWh 1723 kWh £1,364 £172 £1,536 £18,394 12.0 yrs £12,329
8 kW 7878 kWh 5908 kWh 1970 kWh £1,559 £197 £1,756 £20,022 11.4 yrs £15,090

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: £1,113, Upfront: £17,589, Break-even: 15.8 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1970 kWh 1517 kWh 453 kWh £400 £45 £445 £12,706 28.5 yrs £-3,798
3 kW 2954 kWh 2275 kWh 679 kWh £600 £68 £668 £14,333 21.5 yrs £-973
4 kW 3939 kWh 3033 kWh 906 kWh £800 £91 £891 £15,961 17.9 yrs £1,853
5 kW 4924 kWh 3791 kWh 1132 kWh £1,000 £113 £1,113 £17,589 15.8 yrs £4,679
6 kW 5908 kWh 4550 kWh 1359 kWh £1,200 £136 £1,336 £19,217 14.4 yrs £7,505
7 kW 6893 kWh 5308 kWh 1585 kWh £1,400 £159 £1,559 £20,844 13.4 yrs £10,331
8 kW 7878 kWh 6066 kWh 1812 kWh £1,600 £181 £1,781 £22,472 12.6 yrs £13,156

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 Watford

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 WD24

Figures below are tailored to WD24 — click through for full league tables.

Big-Roof Britain Rank #1995 of 2182
4.1 kWp (UK avg 5.1 kWp)
~9 panels (≈430 W)
Solar Payback Index Rank #1205 of 2996
10.0 years (UK avg 10.8 years)
~£815 /yr • £8,139 upfront
Standing-Charge Drag Rank #1280 of 2996
24.2% (UK avg 26.6%) drag on savings
£197 fixed • ~£815 /yr value
Aspect Penalty View ranking →
East −21.6% West −19.3%
Typical output loss versus a south-facing roof (lower is better)

Seasonal solar output in WD24

Monthly generation per kilowatt of solar panels

kWh 39 Jan 52 Feb 84 Mar 110 Apr 117 May 119 Jun 119 Jul 108 Aug 92 Sep 65 Oct 45 Nov 34 Dec
Best month Worst month Winter (Dec–Feb) Other months

Winter output: 50.8% 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 82 kWh. So a typical 4 kW home system would generate roughly 167 kWh in winter, or 328 kWh in an average month.

Your Area at a Glance

Your Electricity Rate
26.38p/kWh
Daily Fixed Charge
53.94p/day
Local Sunshine
985kWh/kW
A 1 kW system generates ~985 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: 56% • Flats: 38% • Bungalows: 2% Based on 6,554 properties

Coverage

Watford (100%)

Areas Covered

Tudor, Callowland, Leggatts, Holywell, Woodside, Central, Nascot, Stanborough

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 Eastern

WD2 (Watford)
≈1.0 km away
Local sunshine: ~992 kWh/kWp · +1% vs WD24
WD17 (Watford)
≈1.3 km away
Local sunshine: ~985 kWh/kWp · -0% vs WD24
WD25 (Watford)
≈1.7 km away
Local sunshine: ~988 kWh/kWp · +0% vs WD24
WD1 (Watford)
≈2.3 km away
Local sunshine: ~991 kWh/kWp · +1% vs WD24
WD99 (Watford)
≈3.1 km away
Local sunshine: ~991 kWh/kWp · +1% vs WD24
WD18 (Watford)
≈3.1 km away
Local sunshine: ~985 kWh/kWp · -0% vs WD24

Similar sunshine across the UK

CF15 (Cardiff)
~985 kWh/kWp · +0% vs WD24
LN1 (Lincoln)
~985 kWh/kWp · -0% vs WD24
LN4 (North Kesteven)
~985 kWh/kWp · +0% vs WD24