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Solar Panels in BT99 (Belfast)

See if solar pays off for you in Belfast — price, savings and payback in under a minute (official UK data).

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
38.3 years
After this, it's pure profit
Upfront Cost
£12,207
What you pay to get started
Annual Benefit
£319
What you save every year
Profit Over 25 Years
£-4,239
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: Bigger systems don’t shorten payback—cost and savings rise together per kW.
  • 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

Costs: Battery prices are typically £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 885 kWh/kW — 105 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 885 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)
885 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: £266, Upfront: £10,173, Break-even: 38.3 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1771 kWh 708 kWh 1062 kWh £0 £106 £106 £4,069 38.3 yrs £-1,944
3 kW 2656 kWh 1062 kWh 1594 kWh £0 £159 £159 £6,104 38.3 yrs £-2,916
4 kW 3542 kWh 1417 kWh 2125 kWh £0 £212 £212 £8,138 38.3 yrs £-3,888
5 kW 4427 kWh 1771 kWh 2656 kWh £0 £266 £266 £10,173 38.3 yrs £-4,860
6 kW 5312 kWh 2125 kWh 3187 kWh £0 £319 £319 £12,207 38.3 yrs £-5,832
7 kW 6198 kWh 2479 kWh 3719 kWh £0 £372 £372 £14,242 38.3 yrs £-6,804
8 kW 7083 kWh 2833 kWh 4250 kWh £0 £425 £425 £16,276 38.3 yrs £-7,776

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

3 kWh battery 5 kW example → Annual benefit: £177, Upfront: £12,273, Break-even: 69.3 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1771 kWh 1062 kWh 708 kWh £0 £71 £71 £6,169 87.1 yrs £-4,752
3 kW 2656 kWh 1594 kWh 1062 kWh £0 £106 £106 £8,204 77.2 yrs £-6,079
4 kW 3542 kWh 2125 kWh 1417 kWh £0 £142 £142 £10,238 72.3 yrs £-7,405
5 kW 4427 kWh 2656 kWh 1771 kWh £0 £177 £177 £12,273 69.3 yrs £-8,731
6 kW 5312 kWh 3187 kWh 2125 kWh £0 £212 £212 £14,307 67.3 yrs £-10,057
7 kW 6198 kWh 3719 kWh 2479 kWh £0 £248 £248 £16,342 65.9 yrs £-11,383
8 kW 7083 kWh 4250 kWh 2833 kWh £0 £283 £283 £18,376 64.9 yrs £-12,710

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

5 kWh battery 5 kW example → Annual benefit: £133, Upfront: £13,673, Break-even: 102.9 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1771 kWh 1240 kWh 531 kWh £0 £53 £53 £7,569 142.5 yrs £-6,507
3 kW 2656 kWh 1859 kWh 797 kWh £0 £80 £80 £9,604 120.5 yrs £-8,010
4 kW 3542 kWh 2479 kWh 1062 kWh £0 £106 £106 £11,638 109.5 yrs £-9,513
5 kW 4427 kWh 3099 kWh 1328 kWh £0 £133 £133 £13,673 102.9 yrs £-11,016
6 kW 5312 kWh 3719 kWh 1594 kWh £0 £159 £159 £15,707 98.6 yrs £-12,520
7 kW 6198 kWh 4338 kWh 1859 kWh £0 £186 £186 £17,742 95.4 yrs £-14,023
8 kW 7083 kWh 4958 kWh 2125 kWh £0 £212 £212 £19,776 93.1 yrs £-15,526

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

7.5 kWh battery 5 kW example → Annual benefit: £120, Upfront: £15,423, Break-even: 129.0 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1771 kWh 1293 kWh 478 kWh £0 £48 £48 £9,319 194.9 yrs £-8,363
3 kW 2656 kWh 1939 kWh 717 kWh £0 £72 £72 £11,354 158.3 yrs £-9,919
4 kW 3542 kWh 2585 kWh 956 kWh £0 £96 £96 £13,388 140.0 yrs £-11,476
5 kW 4427 kWh 3232 kWh 1195 kWh £0 £120 £120 £15,423 129.0 yrs £-13,032
6 kW 5312 kWh 3878 kWh 1434 kWh £0 £143 £143 £17,457 121.7 yrs £-14,588
7 kW 6198 kWh 4524 kWh 1673 kWh £0 £167 £167 £19,492 116.5 yrs £-16,145
8 kW 7083 kWh 5171 kWh 1912 kWh £0 £191 £191 £21,526 112.6 yrs £-17,701

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

10 kWh battery 5 kW example → Annual benefit: £111, Upfront: £17,173, Break-even: 155.2 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1771 kWh 1328 kWh 443 kWh £0 £44 £44 £11,069 250.0 yrs £-10,184
3 kW 2656 kWh 1992 kWh 664 kWh £0 £66 £66 £13,104 197.3 yrs £-11,775
4 kW 3542 kWh 2656 kWh 885 kWh £0 £89 £89 £15,138 171.0 yrs £-13,367
5 kW 4427 kWh 3320 kWh 1107 kWh £0 £111 £111 £17,173 155.2 yrs £-14,959
6 kW 5312 kWh 3984 kWh 1328 kWh £0 £133 £133 £19,207 144.6 yrs £-16,551
7 kW 6198 kWh 4648 kWh 1549 kWh £0 £155 £155 £21,242 137.1 yrs £-18,143
8 kW 7083 kWh 5312 kWh 1771 kWh £0 £177 £177 £23,276 131.4 yrs £-19,735

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

13.5 kWh battery 5 kW example → Annual benefit: £102, Upfront: £19,623, Break-even: 192.7 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1771 kWh 1364 kWh 407 kWh £0 £41 £41 £13,519 331.9 yrs £-12,704
3 kW 2656 kWh 2045 kWh 611 kWh £0 £61 £61 £15,554 254.6 yrs £-14,332
4 kW 3542 kWh 2727 kWh 815 kWh £0 £81 £81 £17,588 215.9 yrs £-15,959
5 kW 4427 kWh 3409 kWh 1018 kWh £0 £102 £102 £19,623 192.7 yrs £-17,586
6 kW 5312 kWh 4091 kWh 1222 kWh £0 £122 £122 £21,657 177.2 yrs £-19,213
7 kW 6198 kWh 4772 kWh 1425 kWh £0 £143 £143 £23,692 166.2 yrs £-20,841
8 kW 7083 kWh 5454 kWh 1629 kWh £0 £163 £163 £25,726 157.9 yrs £-22,468

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, 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.

Your Area at a Glance

Your Electricity Rate
0.00p/kWh
Daily Fixed Charge
0.00p/day
Local Sunshine
885kWh/kW
A 1 kW system generates ~885 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

Belfast (100%)

Areas Covered

Duncairn

Data Sources & Assumptions

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

Electricity rates: Ofgem price cap, Q4 2025

Installation costs: MCS certified installer data, March 2025

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

BT1 (Belfast)
≈0.6 km away
Local sunshine: ~885 kWh/kWp · -0% vs BT99
BT2 (Belfast)
≈1.2 km away
Local sunshine: ~893 kWh/kWp · +1% vs BT99
BT3 (Belfast)
≈1.9 km away
Local sunshine: ~885 kWh/kWp · +0% vs BT99
BT7 (Belfast)
≈1.9 km away
Local sunshine: ~893 kWh/kWp · +1% vs BT99
BT13 (Belfast)
≈2.2 km away
Local sunshine: ~886 kWh/kWp · +0% vs BT99
BT15 (Belfast)
≈2.3 km away
Local sunshine: ~886 kWh/kWp · +0% vs BT99

Similar sunshine across the UK

CA2 (Cumberland)
~885 kWh/kWp · +0% vs BT99
LL15 (Denbighshire)
~885 kWh/kWp · +0% vs BT99
KA7 (South Ayrshire)
~885 kWh/kWp · -0% vs BT99