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Solar panel cost in Chelmsford (CM99)

See realistic solar installation costs, savings and payback for CM99 (Chelmsford) 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
9.5 years
After this, it's pure profit
Upfront Cost
£8,139
What you pay to get started
Annual Benefit
£860
What you save every year
Profit Over 25 Years
£13,366
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 1039 kWh/kW — 30 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 1039 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)
1039 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: £860, Upfront: £8,139, Break-even: 9.5 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2079 kWh 831 kWh 1247 kWh £219 £125 £344 £3,256 9.5 yrs £3,626
3 kW 3118 kWh 1247 kWh 1871 kWh £329 £187 £516 £4,883 9.5 yrs £5,439
4 kW 4157 kWh 1663 kWh 2494 kWh £439 £249 £688 £6,511 9.5 yrs £7,252
5 kW 5197 kWh 2079 kWh 3118 kWh £548 £312 £860 £8,139 9.5 yrs £9,065
6 kW 6236 kWh 2494 kWh 3742 kWh £658 £374 £1,032 £9,767 9.5 yrs £10,878
7 kW 7276 kWh 2910 kWh 4365 kWh £768 £437 £1,204 £11,394 9.5 yrs £12,691
8 kW 8315 kWh 3326 kWh 4989 kWh £877 £499 £1,376 £13,022 9.5 yrs £14,504

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: £1,030, Upfront: £10,239, 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 2079 kWh 1247 kWh 831 kWh £329 £83 £412 £5,356 13.0 yrs £2,888
3 kW 3118 kWh 1871 kWh 1247 kWh £494 £125 £618 £6,983 11.3 yrs £5,382
4 kW 4157 kWh 2494 kWh 1663 kWh £658 £166 £824 £8,611 10.4 yrs £7,876
5 kW 5197 kWh 3118 kWh 2079 kWh £823 £208 £1,030 £10,239 9.9 yrs £10,370
6 kW 6236 kWh 3742 kWh 2494 kWh £987 £249 £1,237 £11,867 9.6 yrs £12,864
7 kW 7276 kWh 4365 kWh 2910 kWh £1,152 £291 £1,443 £13,494 9.4 yrs £15,358
8 kW 8315 kWh 4989 kWh 3326 kWh £1,316 £333 £1,649 £15,122 9.2 yrs £17,852

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: £1,116, Upfront: £11,639, 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 2079 kWh 1455 kWh 624 kWh £384 £62 £446 £6,756 15.1 yrs £2,169
3 kW 3118 kWh 2183 kWh 935 kWh £576 £94 £669 £8,383 12.5 yrs £5,003
4 kW 4157 kWh 2910 kWh 1247 kWh £768 £125 £892 £10,011 11.2 yrs £7,838
5 kW 5197 kWh 3638 kWh 1559 kWh £960 £156 £1,116 £11,639 10.4 yrs £10,672
6 kW 6236 kWh 4365 kWh 1871 kWh £1,152 £187 £1,339 £13,267 9.9 yrs £13,507
7 kW 7276 kWh 5093 kWh 2183 kWh £1,344 £218 £1,562 £14,894 9.5 yrs £16,341
8 kW 8315 kWh 5820 kWh 2494 kWh £1,535 £249 £1,785 £16,522 9.3 yrs £19,176

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: £1,141, Upfront: £13,389, Break-even: 11.7 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2079 kWh 1517 kWh 561 kWh £400 £56 £456 £8,506 18.6 yrs £623
3 kW 3118 kWh 2276 kWh 842 kWh £600 £84 £685 £10,133 14.8 yrs £3,560
4 kW 4157 kWh 3035 kWh 1123 kWh £801 £112 £913 £11,761 12.9 yrs £6,496
5 kW 5197 kWh 3794 kWh 1403 kWh £1,001 £140 £1,141 £13,389 11.7 yrs £9,433
6 kW 6236 kWh 4552 kWh 1684 kWh £1,201 £168 £1,369 £15,017 11.0 yrs £12,370
7 kW 7276 kWh 5311 kWh 1964 kWh £1,401 £196 £1,598 £16,644 10.4 yrs £15,306
8 kW 8315 kWh 6070 kWh 2245 kWh £1,601 £225 £1,826 £18,272 10.0 yrs £18,243

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: £1,158, Upfront: £15,139, Break-even: 13.1 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2079 kWh 1559 kWh 520 kWh £411 £52 £463 £10,256 22.1 yrs £-991
3 kW 3118 kWh 2339 kWh 780 kWh £617 £78 £695 £11,883 17.1 yrs £2,014
4 kW 4157 kWh 3118 kWh 1039 kWh £823 £104 £926 £13,511 14.6 yrs £5,019
5 kW 5197 kWh 3898 kWh 1299 kWh £1,028 £130 £1,158 £15,139 13.1 yrs £8,024
6 kW 6236 kWh 4677 kWh 1559 kWh £1,234 £156 £1,390 £16,767 12.1 yrs £11,028
7 kW 7276 kWh 5457 kWh 1819 kWh £1,439 £182 £1,621 £18,394 11.3 yrs £14,033
8 kW 8315 kWh 6236 kWh 2079 kWh £1,645 £208 £1,853 £20,022 10.8 yrs £17,038

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: £1,175, Upfront: £17,589, Break-even: 15.0 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2079 kWh 1601 kWh 478 kWh £422 £48 £470 £12,706 27.0 yrs £-3,304
3 kW 3118 kWh 2401 kWh 717 kWh £633 £72 £705 £14,333 20.3 yrs £-232
4 kW 4157 kWh 3201 kWh 956 kWh £844 £96 £940 £15,961 17.0 yrs £2,841
5 kW 5197 kWh 4002 kWh 1195 kWh £1,056 £120 £1,175 £17,589 15.0 yrs £5,914
6 kW 6236 kWh 4802 kWh 1434 kWh £1,267 £143 £1,410 £19,217 13.6 yrs £8,987
7 kW 7276 kWh 5602 kWh 1673 kWh £1,478 £167 £1,645 £20,844 12.7 yrs £12,060
8 kW 8315 kWh 6403 kWh 1912 kWh £1,689 £191 £1,880 £22,472 12.0 yrs £15,132

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 Chelmsford

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 CM99

Figures below are tailored to CM99 — click through for full league tables.

Solar Payback Index Rank #276 of 2996
9.5 years (UK avg 10.8 years)
~£860 /yr • £8,139 upfront
Standing-Charge Drag Rank #991 of 2996
22.9% (UK avg 26.6%) drag on savings
£197 fixed • ~£860 /yr value
Aspect Penalty View ranking →
East −21.9% West −20.4%
Typical output loss versus a south-facing roof (lower is better)

Seasonal solar output in CM99

Monthly generation per kilowatt of solar panels

kWh 40 Jan 54 Feb 88 Mar 116 Apr 123 May 125 Jun 126 Jul 114 Aug 98 Sep 70 Oct 49 Nov 36 Dec
Best month Worst month Winter (Dec–Feb) Other months

Winter output: 50.1% 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 43 kWh per month; the average month produces around 87 kWh. So a typical 4 kW home system would generate roughly 174 kWh in winter, or 346 kWh in an average month.

Your Area at a Glance

Your Electricity Rate
26.38p/kWh
Daily Fixed Charge
53.94p/day
Local Sunshine
1039kWh/kW
A 1 kW system generates ~1039 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

No EPC data available for this outcode

Coverage

Chelmsford (100%)

Areas Covered

Chelmer Village and Beaulieu Park, Moulsham and Central, Great Baddow East

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

CM98 (Chelmsford)
≈1.7 km away
Local sunshine: ~1,036 kWh/kWp · -0% vs CM99
CM1 (Chelmsford)
≈1.9 km away
Local sunshine: ~1,033 kWh/kWp · -1% vs CM99
CM2 (Chelmsford)
≈2.4 km away
Local sunshine: ~1,033 kWh/kWp · -1% vs CM99
CM3 (Chelmsford)
≈6.9 km away
Local sunshine: ~1,035 kWh/kWp · -0% vs CM99
CM4 (Brentwood)
≈11.5 km away
Local sunshine: ~1,023 kWh/kWp · -2% vs CM99
CM8 (Braintree)
≈11.5 km away
Local sunshine: ~1,050 kWh/kWp · +1% vs CM99

Similar sunshine across the UK

SA71 (Pembrokeshire)
~1,039 kWh/kWp · -0% vs CM99
SA72 (Pembrokeshire)
~1,040 kWh/kWp · +0% vs CM99
ME4 (Medway)
~1,040 kWh/kWp · +0% vs CM99