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Solar panel cost in Isles of Scilly (TR25)

See realistic solar installation costs, savings and payback for TR25 (Isles of Scilly) 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
9.0 years
After this, it's pure profit
Upfront Cost
£9,767
What you pay to get started
Annual Benefit
£1,084
What you save every year
Profit Over 25 Years
£17,340
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 Western, the current unit rate is 26.39p/kWh with a 57.89p/day standing charge. Your postcode’s south-facing sunshine yield is 1092 kWh/kW — 78 above the regional median (1013).

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 1092 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
57.9p/day
Sunshine yield (south)
1092 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: £904, Upfront: £8,139, Break-even: 9.0 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2183 kWh 873 kWh 1310 kWh £230 £131 £361 £3,256 9.0 yrs £3,973
3 kW 3274 kWh 1310 kWh 1965 kWh £346 £196 £542 £4,883 9.0 yrs £5,959
4 kW 4366 kWh 1746 kWh 2620 kWh £461 £262 £723 £6,511 9.0 yrs £7,946
5 kW 5458 kWh 2183 kWh 3274 kWh £576 £327 £904 £8,139 9.0 yrs £9,932
6 kW 6549 kWh 2620 kWh 3929 kWh £691 £393 £1,084 £9,767 9.0 yrs £11,918
7 kW 7640 kWh 3056 kWh 4584 kWh £807 £458 £1,265 £11,394 9.0 yrs £13,905
8 kW 8732 kWh 3493 kWh 5239 kWh £922 £524 £1,446 £13,022 9.0 yrs £15,891

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: £1,082, Upfront: £10,239, 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 2183 kWh 1310 kWh 873 kWh £346 £87 £433 £5,356 12.4 yrs £3,304
3 kW 3274 kWh 1965 kWh 1310 kWh £518 £131 £649 £6,983 10.8 yrs £6,006
4 kW 4366 kWh 2620 kWh 1746 kWh £691 £175 £866 £8,611 9.9 yrs £8,708
5 kW 5458 kWh 3274 kWh 2183 kWh £864 £218 £1,082 £10,239 9.5 yrs £11,410
6 kW 6549 kWh 3929 kWh 2620 kWh £1,037 £262 £1,299 £11,867 9.1 yrs £14,112
7 kW 7640 kWh 4584 kWh 3056 kWh £1,210 £306 £1,515 £13,494 8.9 yrs £16,814
8 kW 8732 kWh 5239 kWh 3493 kWh £1,383 £349 £1,732 £15,122 8.7 yrs £19,516

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: £1,172, Upfront: £11,639, 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 2183 kWh 1528 kWh 655 kWh £403 £65 £469 £6,756 14.4 yrs £2,620
3 kW 3274 kWh 2292 kWh 982 kWh £605 £98 £703 £8,383 11.9 yrs £5,679
4 kW 4366 kWh 3056 kWh 1310 kWh £807 £131 £938 £10,011 10.7 yrs £8,739
5 kW 5458 kWh 3820 kWh 1637 kWh £1,008 £164 £1,172 £11,639 9.9 yrs £11,799
6 kW 6549 kWh 4584 kWh 1965 kWh £1,210 £196 £1,406 £13,267 9.4 yrs £14,859
7 kW 7640 kWh 5348 kWh 2292 kWh £1,411 £229 £1,641 £14,894 9.1 yrs £17,919
8 kW 8732 kWh 6112 kWh 2620 kWh £1,613 £262 £1,875 £16,522 8.8 yrs £20,978

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: £1,199, Upfront: £13,389, Break-even: 11.2 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2183 kWh 1594 kWh 589 kWh £421 £59 £479 £8,506 17.7 yrs £1,084
3 kW 3274 kWh 2390 kWh 884 kWh £631 £88 £719 £10,133 14.1 yrs £4,251
4 kW 4366 kWh 3187 kWh 1179 kWh £841 £118 £959 £11,761 12.3 yrs £7,419
5 kW 5458 kWh 3984 kWh 1474 kWh £1,051 £147 £1,199 £13,389 11.2 yrs £10,586
6 kW 6549 kWh 4781 kWh 1768 kWh £1,262 £177 £1,438 £15,017 10.4 yrs £13,753
7 kW 7640 kWh 5578 kWh 2063 kWh £1,472 £206 £1,678 £16,644 9.9 yrs £16,920
8 kW 8732 kWh 6374 kWh 2358 kWh £1,682 £236 £1,918 £18,272 9.5 yrs £20,087

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: £1,217, Upfront: £15,139, 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 2183 kWh 1637 kWh 546 kWh £432 £55 £487 £10,256 21.1 yrs £-523
3 kW 3274 kWh 2456 kWh 819 kWh £648 £82 £730 £11,883 16.3 yrs £2,716
4 kW 4366 kWh 3274 kWh 1092 kWh £864 £109 £973 £13,511 13.9 yrs £5,955
5 kW 5458 kWh 4093 kWh 1364 kWh £1,080 £136 £1,217 £15,139 12.4 yrs £9,193
6 kW 6549 kWh 4912 kWh 1637 kWh £1,296 £164 £1,460 £16,767 11.5 yrs £12,432
7 kW 7640 kWh 5730 kWh 1910 kWh £1,512 £191 £1,703 £18,394 10.8 yrs £15,671
8 kW 8732 kWh 6549 kWh 2183 kWh £1,728 £218 £1,947 £20,022 10.3 yrs £18,910

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: £1,235, Upfront: £17,589, Break-even: 14.2 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2183 kWh 1681 kWh 502 kWh £444 £50 £494 £12,706 25.7 yrs £-2,829
3 kW 3274 kWh 2521 kWh 753 kWh £665 £75 £741 £14,333 19.4 yrs £481
4 kW 4366 kWh 3362 kWh 1004 kWh £887 £100 £988 £15,961 16.2 yrs £3,791
5 kW 5458 kWh 4202 kWh 1255 kWh £1,109 £126 £1,235 £17,589 14.2 yrs £7,101
6 kW 6549 kWh 5043 kWh 1506 kWh £1,331 £151 £1,481 £19,217 13.0 yrs £10,412
7 kW 7640 kWh 5883 kWh 1757 kWh £1,553 £176 £1,728 £20,844 12.1 yrs £13,722
8 kW 8732 kWh 6724 kWh 2008 kWh £1,774 £201 £1,975 £22,472 11.4 yrs £17,032

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 Isles of Scilly

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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Check what MCS certification means

Understand DNO, G98 and G99 export limits

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Insights for TR25

Figures below are tailored to TR25 — click through for full league tables.

Big-Roof Britain Rank #335 of 2182
5.8 kWp (UK avg 5.1 kWp)
~12 panels (≈430 W)
Solar Payback Index Rank #120 of 2996
9.0 years (UK avg 10.8 years)
~£1,085 /yr • £9,767 upfront
Standing-Charge Drag Rank #385 of 2996
19.4% (UK avg 26.6%) drag on savings
£211 fixed • ~£1,085 /yr value
Aspect Penalty View ranking →
East −19.2% West −22.3%
Typical output loss versus a south-facing roof (lower is better)

Seasonal solar output in TR25

Monthly generation per kilowatt of solar panels

kWh 38 Jan 56 Feb 89 Mar 127 Apr 136 May 135 Jun 133 Jul 125 Aug 101 Sep 73 Oct 45 Nov 32 Dec
Best month Worst month Winter (Dec–Feb) Other months

Winter output: 46.5% of an average month (Dec–Feb)

Best / worst month: May / 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 91 kWh. So a typical 4 kW home system would generate roughly 169 kWh in winter, or 364 kWh in an average month.

Your Area at a Glance

Your Electricity Rate
26.39p/kWh
Daily Fixed Charge
57.89p/day
Local Sunshine
1092kWh/kW
A 1 kW system generates ~1092 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: 69% • Flats: 0% • Bungalows: 28% Based on 36 properties

Coverage

Isles of Scilly (100%)

Areas Covered

St Martin's

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 Western

TR24 (Isles of Scilly)
≈3.5 km away
Local sunshine: ~1,096 kWh/kWp · +0% vs TR25
TR23 (Isles of Scilly)
≈4.6 km away
Local sunshine: ~1,101 kWh/kWp · +1% vs TR25
TR21 (Isles of Scilly)
≈5.6 km away
Local sunshine: ~1,066 kWh/kWp · -2% vs TR25
TR22 (Isles of Scilly)
≈8.6 km away
Local sunshine: ~1,099 kWh/kWp · +1% vs TR25
TR19 (Cornwall)
≈47.5 km away
Local sunshine: ~1,083 kWh/kWp · -1% vs TR25
TR18 (Cornwall)
≈56.3 km away
Local sunshine: ~1,066 kWh/kWp · -2% vs TR25

Similar sunshine across the UK

BH8 (Bournemouth, Christchurch and Poole)
~1,092 kWh/kWp · +0% vs TR25
CT8 (Thanet)
~1,092 kWh/kWp · +0% vs TR25
CT7 (Thanet)
~1,091 kWh/kWp · -0% vs TR25