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Solar panel cost in East Hertfordshire (CM21)

See realistic solar installation costs, savings and payback for CM21 (East Hertfordshire) 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
9.7 years
After this, it's pure profit
Upfront Cost
£8,139
What you pay to get started
Annual Benefit
£837
What you save every year
Profit Over 25 Years
£12,777
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 1011 kWh/kW — 2 above 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 1011 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)
1011 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: £837, Upfront: £8,139, Break-even: 9.7 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2022 kWh 809 kWh 1213 kWh £213 £121 £335 £3,256 9.7 yrs £3,438
3 kW 3033 kWh 1213 kWh 1820 kWh £320 £182 £502 £4,883 9.7 yrs £5,156
4 kW 4044 kWh 1617 kWh 2426 kWh £427 £243 £669 £6,511 9.7 yrs £6,875
5 kW 5055 kWh 2022 kWh 3033 kWh £533 £303 £837 £8,139 9.7 yrs £8,594
6 kW 6066 kWh 2426 kWh 3639 kWh £640 £364 £1,004 £9,767 9.7 yrs £10,313
7 kW 7077 kWh 2831 kWh 4246 kWh £747 £425 £1,171 £11,394 9.7 yrs £12,032
8 kW 8087 kWh 3235 kWh 4852 kWh £853 £485 £1,339 £13,022 9.7 yrs £13,751

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: £1,002, Upfront: £10,239, Break-even: 10.2 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2022 kWh 1213 kWh 809 kWh £320 £81 £401 £5,356 13.4 yrs £2,662
3 kW 3033 kWh 1820 kWh 1213 kWh £480 £121 £601 £6,983 11.6 yrs £5,044
4 kW 4044 kWh 2426 kWh 1617 kWh £640 £162 £802 £8,611 10.7 yrs £7,425
5 kW 5055 kWh 3033 kWh 2022 kWh £800 £202 £1,002 £10,239 10.2 yrs £9,806
6 kW 6066 kWh 3639 kWh 2426 kWh £960 £243 £1,203 £11,867 9.9 yrs £12,187
7 kW 7077 kWh 4246 kWh 2831 kWh £1,120 £283 £1,403 £13,494 9.6 yrs £14,568
8 kW 8087 kWh 4852 kWh 3235 kWh £1,280 £323 £1,604 £15,122 9.4 yrs £16,949

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: £1,085, Upfront: £11,639, Break-even: 10.7 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2022 kWh 1415 kWh 607 kWh £373 £61 £434 £6,756 15.6 yrs £1,925
3 kW 3033 kWh 2123 kWh 910 kWh £560 £91 £651 £8,383 12.9 yrs £4,637
4 kW 4044 kWh 2831 kWh 1213 kWh £747 £121 £868 £10,011 11.5 yrs £7,349
5 kW 5055 kWh 3538 kWh 1516 kWh £933 £152 £1,085 £11,639 10.7 yrs £10,062
6 kW 6066 kWh 4246 kWh 1820 kWh £1,120 £182 £1,302 £13,267 10.2 yrs £12,774
7 kW 7077 kWh 4954 kWh 2123 kWh £1,307 £212 £1,519 £14,894 9.8 yrs £15,487
8 kW 8087 kWh 5661 kWh 2426 kWh £1,493 £243 £1,736 £16,522 9.5 yrs £18,199

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: £1,110, Upfront: £13,389, Break-even: 12.1 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2022 kWh 1476 kWh 546 kWh £389 £55 £444 £8,506 19.2 yrs £373
3 kW 3033 kWh 2214 kWh 819 kWh £584 £82 £666 £10,133 15.2 yrs £3,185
4 kW 4044 kWh 2952 kWh 1092 kWh £779 £109 £888 £11,761 13.2 yrs £5,997
5 kW 5055 kWh 3690 kWh 1365 kWh £973 £136 £1,110 £13,389 12.1 yrs £8,809
6 kW 6066 kWh 4428 kWh 1638 kWh £1,168 £164 £1,332 £15,017 11.3 yrs £11,620
7 kW 7077 kWh 5166 kWh 1911 kWh £1,363 £191 £1,554 £16,644 10.7 yrs £14,432
8 kW 8087 kWh 5904 kWh 2184 kWh £1,557 £218 £1,776 £18,272 10.3 yrs £17,244

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: £1,126, Upfront: £15,139, Break-even: 13.4 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2022 kWh 1516 kWh 505 kWh £400 £51 £451 £10,256 22.8 yrs £-1,244
3 kW 3033 kWh 2275 kWh 758 kWh £600 £76 £676 £11,883 17.6 yrs £1,634
4 kW 4044 kWh 3033 kWh 1011 kWh £800 £101 £901 £13,511 15.0 yrs £4,512
5 kW 5055 kWh 3791 kWh 1264 kWh £1,000 £126 £1,126 £15,139 13.4 yrs £7,390
6 kW 6066 kWh 4549 kWh 1516 kWh £1,200 £152 £1,352 £16,767 12.4 yrs £10,268
7 kW 7077 kWh 5307 kWh 1769 kWh £1,400 £177 £1,577 £18,394 11.7 yrs £13,146
8 kW 8087 kWh 6066 kWh 2022 kWh £1,600 £202 £1,802 £20,022 11.1 yrs £16,024

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: £1,143, Upfront: £17,589, Break-even: 15.4 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2022 kWh 1557 kWh 465 kWh £411 £47 £457 £12,706 27.8 yrs £-3,562
3 kW 3033 kWh 2335 kWh 698 kWh £616 £70 £686 £14,333 20.9 yrs £-617
4 kW 4044 kWh 3114 kWh 930 kWh £821 £93 £914 £15,961 17.5 yrs £2,327
5 kW 5055 kWh 3892 kWh 1163 kWh £1,027 £116 £1,143 £17,589 15.4 yrs £5,271
6 kW 6066 kWh 4670 kWh 1395 kWh £1,232 £140 £1,372 £19,217 14.0 yrs £8,215
7 kW 7077 kWh 5449 kWh 1628 kWh £1,437 £163 £1,600 £20,844 13.0 yrs £11,159
8 kW 8087 kWh 6227 kWh 1860 kWh £1,643 £186 £1,829 £22,472 12.3 yrs £14,104

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 East Hertfordshire

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 CM21

Figures below are tailored to CM21 — click through for full league tables.

Big-Roof Britain Rank #1325 of 2182
4.8 kWp (UK avg 5.1 kWp)
~10 panels (≈430 W)
Solar Payback Index Rank #445 of 2996
9.7 years (UK avg 10.8 years)
~£837 /yr • £8,139 upfront
Standing-Charge Drag Rank #1076 of 2996
23.5% (UK avg 26.6%) drag on savings
£197 fixed • ~£837 /yr value
Aspect Penalty View ranking →
East −21.7% West −19.8%
Typical output loss versus a south-facing roof (lower is better)

Seasonal solar output in CM21

Monthly generation per kilowatt of solar panels

kWh 39 Jan 53 Feb 86 Mar 114 Apr 119 May 122 Jun 122 Jul 111 Aug 95 Sep 68 Oct 46 Nov 35 Dec
Best month Worst month Winter (Dec–Feb) Other months

Winter output: 49.9% of an average month (Dec–Feb)

Best / worst month: Jun / 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 84 kWh. So a typical 4 kW home system would generate roughly 168 kWh in winter, or 337 kWh in an average month.

Your Area at a Glance

Your Electricity Rate
26.38p/kWh
Daily Fixed Charge
53.94p/day
Local Sunshine
1011kWh/kW
A 1 kW system generates ~1011 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: 63% • Flats: 28% • Bungalows: 7% Based on 2,982 properties

Coverage

East Hertfordshire (69%)|Epping Forest (31%)

Areas Covered

Sawbridgeworth, Rural East, Much Hadham, Old Harlow

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

CM17 (Harlow)
≈4.5 km away
Local sunshine: ~1,012 kWh/kWp · +0% vs CM21
CM20 (Harlow)
≈6.0 km away
Local sunshine: ~1,006 kWh/kWp · -0% vs CM21
CM23 (East Hertfordshire)
≈6.1 km away
Local sunshine: ~1,004 kWh/kWp · -1% vs CM21
SG10 (East Hertfordshire)
≈6.5 km away
Local sunshine: ~1,008 kWh/kWp · -0% vs CM21
CM18 (Harlow)
≈7.0 km away
Local sunshine: ~1,012 kWh/kWp · +0% vs CM21
CM19 (Harlow)
≈7.3 km away
Local sunshine: ~1,006 kWh/kWp · -0% vs CM21

Similar sunshine across the UK

TA20 (Somerset)
~1,011 kWh/kWp · -0% vs CM21
GU33 (East Hampshire)
~1,011 kWh/kWp · -0% vs CM21
SP10 (Test Valley)
~1,011 kWh/kWp · +0% vs CM21