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Solar panel cost in Lisburn and Castlereagh (BT8)

See realistic solar installation costs, savings and payback for BT8 (Lisburn and Castlereagh) 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
30.4 years
After this, it's pure profit
Upfront Cost
£9,767
What you pay to get started
Annual Benefit
£321
What you save every year
Profit Over 25 Years
£-1,747
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 Northern Ireland, the current unit rate is 0.00p/kWh with a 0.00p/day standing charge. Your postcode’s south-facing sunshine yield is 891 kWh/kW — 100 below the regional median (991).

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 891 kWh per year on a south-facing roof. We value self-used electricity at 0.0p and exported surplus at a baseline 10p via SEG. Use the calculator above for your exact tariff.

Unit rate
0.0p/kWh
Standing charge
0.0p/day
Sunshine yield (south)
891 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: £267, Upfront: £8,139, Break-even: 30.4 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1782 kWh 713 kWh 1069 kWh £0 £107 £107 £3,256 30.4 yrs £-1,117
3 kW 2673 kWh 1069 kWh 1604 kWh £0 £160 £160 £4,883 30.4 yrs £-1,676
4 kW 3564 kWh 1426 kWh 2138 kWh £0 £214 £214 £6,511 30.4 yrs £-2,234
5 kW 4455 kWh 1782 kWh 2673 kWh £0 £267 £267 £8,139 30.4 yrs £-2,793
6 kW 5346 kWh 2138 kWh 3208 kWh £0 £321 £321 £9,767 30.4 yrs £-3,351
7 kW 6237 kWh 2495 kWh 3742 kWh £0 £374 £374 £11,394 30.4 yrs £-3,910
8 kW 7128 kWh 2851 kWh 4277 kWh £0 £428 £428 £13,022 30.4 yrs £-4,468

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: £178, Upfront: £10,239, Break-even: 57.5 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1782 kWh 1069 kWh 713 kWh £0 £71 £71 £5,356 75.1 yrs £-3,930
3 kW 2673 kWh 1604 kWh 1069 kWh £0 £107 £107 £6,983 65.3 yrs £-4,845
4 kW 3564 kWh 2138 kWh 1426 kWh £0 £143 £143 £8,611 60.4 yrs £-5,760
5 kW 4455 kWh 2673 kWh 1782 kWh £0 £178 £178 £10,239 57.5 yrs £-6,675
6 kW 5346 kWh 3208 kWh 2138 kWh £0 £214 £214 £11,867 55.5 yrs £-7,590
7 kW 6237 kWh 3742 kWh 2495 kWh £0 £249 £249 £13,494 54.1 yrs £-8,505
8 kW 7128 kWh 4277 kWh 2851 kWh £0 £285 £285 £15,122 53.0 yrs £-9,419

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: £134, Upfront: £11,639, Break-even: 87.1 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1782 kWh 1247 kWh 535 kWh £0 £53 £53 £6,756 126.4 yrs £-5,686
3 kW 2673 kWh 1871 kWh 802 kWh £0 £80 £80 £8,383 104.5 yrs £-6,779
4 kW 3564 kWh 2495 kWh 1069 kWh £0 £107 £107 £10,011 93.6 yrs £-7,873
5 kW 4455 kWh 3119 kWh 1337 kWh £0 £134 £134 £11,639 87.1 yrs £-8,966
6 kW 5346 kWh 3742 kWh 1604 kWh £0 £160 £160 £13,267 82.7 yrs £-10,059
7 kW 6237 kWh 4366 kWh 1871 kWh £0 £187 £187 £14,894 79.6 yrs £-11,152
8 kW 7128 kWh 4990 kWh 2138 kWh £0 £214 £214 £16,522 77.3 yrs £-12,245

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: £120, Upfront: £13,389, Break-even: 111.3 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1782 kWh 1301 kWh 481 kWh £0 £48 £48 £8,506 176.8 yrs £-7,543
3 kW 2673 kWh 1951 kWh 722 kWh £0 £72 £72 £10,133 140.4 yrs £-8,690
4 kW 3564 kWh 2602 kWh 962 kWh £0 £96 £96 £11,761 122.2 yrs £-9,836
5 kW 4455 kWh 3252 kWh 1203 kWh £0 £120 £120 £13,389 111.3 yrs £-10,983
6 kW 5346 kWh 3903 kWh 1443 kWh £0 £144 £144 £15,017 104.0 yrs £-12,130
7 kW 6237 kWh 4553 kWh 1684 kWh £0 £168 £168 £16,644 98.8 yrs £-13,276
8 kW 7128 kWh 5204 kWh 1925 kWh £0 £192 £192 £18,272 94.9 yrs £-14,423

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: £111, Upfront: £15,139, Break-even: 135.9 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1782 kWh 1337 kWh 446 kWh £0 £45 £45 £10,256 230.2 yrs £-9,364
3 kW 2673 kWh 2005 kWh 668 kWh £0 £67 £67 £11,883 177.8 yrs £-10,547
4 kW 3564 kWh 2673 kWh 891 kWh £0 £89 £89 £13,511 151.6 yrs £-11,729
5 kW 4455 kWh 3341 kWh 1114 kWh £0 £111 £111 £15,139 135.9 yrs £-12,911
6 kW 5346 kWh 4010 kWh 1337 kWh £0 £134 £134 £16,767 125.4 yrs £-14,093
7 kW 6237 kWh 4678 kWh 1559 kWh £0 £156 £156 £18,394 118.0 yrs £-15,276
8 kW 7128 kWh 5346 kWh 1782 kWh £0 £178 £178 £20,022 112.4 yrs £-16,458

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: £102, Upfront: £17,589, Break-even: 171.7 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1782 kWh 1372 kWh 410 kWh £0 £41 £41 £12,706 310.0 yrs £-11,886
3 kW 2673 kWh 2058 kWh 615 kWh £0 £61 £61 £14,333 233.1 yrs £-13,104
4 kW 3564 kWh 2744 kWh 820 kWh £0 £82 £82 £15,961 194.7 yrs £-14,322
5 kW 4455 kWh 3430 kWh 1025 kWh £0 £102 £102 £17,589 171.7 yrs £-15,539
6 kW 5346 kWh 4117 kWh 1230 kWh £0 £123 £123 £19,217 156.3 yrs £-16,757
7 kW 6237 kWh 4803 kWh 1435 kWh £0 £143 £143 £20,844 145.3 yrs £-17,975
8 kW 7128 kWh 5489 kWh 1639 kWh £0 £164 £164 £22,472 137.1 yrs £-19,193

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 Lisburn and Castlereagh

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 BT8

Figures below are tailored to BT8 — click through for full league tables.

Aspect Penalty View ranking →
East −20.8% West −20.5%
Typical output loss versus a south-facing roof (lower is better)

Seasonal solar output in BT8

Monthly generation per kilowatt of solar panels

kWh 29 Jan 46 Feb 78 Mar 105 Apr 118 May 112 Jun 107 Jul 98 Aug 79 Sep 57 Oct 37 Nov 25 Dec
Best month Worst month Winter (Dec–Feb) Other months

Winter output: 45.0% 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 33 kWh per month; the average month produces around 74 kWh. So a typical 4 kW home system would generate roughly 134 kWh in winter, or 297 kWh in an average month.

Your Area at a Glance

Your Electricity Rate
0.00p/kWh
Daily Fixed Charge
0.00p/day
Local Sunshine
891kWh/kW
A 1 kW system generates ~891 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

No EPC data available for this outcode

Coverage

Lisburn and Castlereagh (78%)|Belfast (22%)

Areas Covered

Belvoir, Beechill, Newtownbreda, Galwally, Knockbracken, Carryduff West, Cairnshill, Carryduff East + 4 more

Data Sources & Assumptions

Solar yield: PVGIS (EU Joint Research Centre), January 2025 data

Electricity rates: Ofgem price cap,

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 Northern Ireland

BT6 (Belfast)
≈3.6 km away
Local sunshine: ~892 kWh/kWp · +0% vs BT8
BT9 (Belfast)
≈3.7 km away
Local sunshine: ~893 kWh/kWp · +0% vs BT8
BT7 (Belfast)
≈4.1 km away
Local sunshine: ~893 kWh/kWp · +0% vs BT8
BT5 (Belfast)
≈4.9 km away
Local sunshine: ~892 kWh/kWp · +0% vs BT8
BT2 (Belfast)
≈5.2 km away
Local sunshine: ~893 kWh/kWp · +0% vs BT8
BT10 (Belfast)
≈5.2 km away
Local sunshine: ~884 kWh/kWp · -1% vs BT8

Similar sunshine across the UK

AB43 (Aberdeenshire)
~891 kWh/kWp · -0% vs BT8
PR26 (South Ribble)
~891 kWh/kWp · -0% vs BT8
M31 (Trafford)
~891 kWh/kWp · -0% vs BT8