How much will solar panels produce in Belfast?

A 4 kWp system facing south at 35° tilt in Belfast produces about 3,679 kWh a year. In a weak year that is 3,078 kWh, in a good one 4,280 kWh — 920 kWh per kWp.

That’s about 136% of a typical home’s yearly use (2,700 kWh).

Calculate for my roof

Based on 2014–2023 satellite weather data

Production by month

0200400600800JanJanuary: 4 kWp 106 kWh, range 81–131FebFebruary: 4 kWp 195 kWh, range 147–244MarMarch: 4 kWp 313 kWh, range 251–375AprApril: 4 kWp 401 kWh, range 301–501MayMay: 4 kWp 507 kWh, range 406–608JunJune: 4 kWp 472 kWh, range 377–568JulJuly: 4 kWp 426 kWh, range 348–503AugAugust: 4 kWp 411 kWh, range 340–482SepSeptember: 4 kWp 334 kWh, range 273–394OctOctober: 4 kWp 227 kWh, range 180–274NovNovember: 4 kWp 132 kWh, range 98–166DecDecember: 4 kWp 93 kWh, range 66–120

kWh per month

A typical day in May

The sunniest month in Belfast. Output peaks around 12:00 solar time, at about 1.9 kWh in the best hour.

0:006:0012:0018:0023:00 1.9 0

Month by month

Month Weak year, kWh Typical year, kWh Good year, kWh
January 81 106 131
February 147 195 244
March 251 313 375
April 301 401 501
May 406 507 608
June 377 472 568
July 348 426 503
August 340 411 482
September 273 334 394
October 180 227 274
November 98 132 166
December 66 93 120
Year 3,078 3,679 4,280

The months don’t add up exactly to the yearly figure, because each one is the typical value across many years.

Common questions

How much do solar panels produce in winter in Belfast?

From November to February the system produces about 527 kWh, which is 15% of the year. The weakest month (December) gives roughly 93 kWh.

Is an east-west roof worth it in Belfast?

An east-west system typically produces 10–25% less per kWp than one facing south, but spreads production more evenly through the day. The exact difference depends on tilt and shading.

Compare an east-west roof for Belfast

Ground mount or roof in Belfast?

A ground mount can be tilted and aimed freely, which can add some yield, but it costs more and needs space. Compare both for your own plot.

Check a ground-mounted system in Belfast

Your roof is not an average roof

Set your own tilt, direction, shading and inverter limit and get a range for your address.

Calculate for my roof

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Climate data: Photovoltaic Geographical Information System (PVGIS) — European Commission, Joint Research Centre