Solar Panel Cost in Ireland: Turning a Quote Into a Payback Figure

Key Takeaways

• We do not publish a national installed cost for Irish solar, because nobody has surveyed it and the "average cost" figures in circulation are not traceable to one. Costs are quote-only here.
• What we can source is generation: PVGIS models roughly 977 kWh per kWp per year in Dublin, 1,009 in Cork and 910 in Galway at optimum tilt.
• Two of the four numbers in a payback sum are on your own bill and quote, which is why any payback figure offered before an installer has seen your roof is guesswork.
• The SEAI grant is a one-off cut of up to €1,800. The export rate is recurring, and one supplier is cutting it by roughly a quarter in 2026.

Why we will not quote you an average cost

Every Irish solar page has a number for this, and almost none of them says where it came from. We survey prices and publish them with the date and the source, or we do not publish them — and we have not yet surveyed Irish installers.

That is not evasion. Irish residential solar is genuinely sold by quotation: the same 4 kWp array costs differently on a slate roof and a tile roof, on a two-storey and a bungalow, with and without scaffolding, in Dublin and in Leitrim. A single national average conceals exactly the variation you are trying to price.

So this page gives you the numbers that are knowable, and the method to apply them to the quote in your hand.

How much will it actually generate?

This one is modellable, and the European Commission's PVGIS tool is the reference. At the optimum tilt for each location — around 40°, facing south — with 14% system losses:

PVGIS v5.2, PVGIS-SARAH2 radiation database (2005–2020), read 9 August 2026. Modelled at optimum angles with 14% system loss.

Three things worth taking from that table.

Ireland is not too far north for solar. Just under 1,000 kWh per kWp is a real number, and the roughly 10% spread between Cork and Galway is smaller than the spread your own roof pitch will introduce.

The optimum tilt is about 40°, which is close to a typical Irish pitched roof — so most houses are not giving up much to geometry.

These are modelled, not measured. PVGIS reports a year-to-year standard deviation of about 27 kWh/kWp for Dublin, so treat the figure as a central estimate rather than a promise. A south-east or south-west facing roof will come in below it.

The four numbers that decide payback

Only the second is something a stranger can tell you. That is the honest reason payback figures vary so wildly between sales pitches: two of the four inputs are private to your household, and a third is set by whichever supplier you happen to be on.

The method

1. Net cost. Take the quote. Subtract the SEAI grant — €700 per kWp for the first 2 kWp, €200 per kWp to a maximum of €1,800.
2. Annual generation. Multiply your system size in kWp by the figure for your nearest city above. Reduce it if your roof faces east or west rather than south.
3. Split that generation. Estimate what fraction you will use in the house versus export. A household that is empty on weekdays self-consumes far less than one that is not.
4. Value each part differently. Self-consumed units are worth your import rate, because you avoid paying it. Exported units are worth your export rate. These are not the same number and the gap is the whole game.
5. Divide. Net cost ÷ annual value = payback in years.

Step 4 is where most quoted paybacks quietly cheat, by valuing all generation at the import rate as though none of it were exported.

Why the split matters more than the size

Because the export rate is below the import rate, a unit you use is worth more than a unit you sell — and at least one supplier is widening that gap in 2026, cutting its export rate from 25c to 18.5c per kWh ex VAT from 1 August.

The consequence for sizing is direct: capacity beyond what you can consume during daylight earns the lower rate. Under a generous export regime, a bigger array is close to self-funding; under a reduced one, it argues for sizing to your daytime demand rather than to your available roof.

It also compounds with the grant's shape, which pays €700 per kWp for the first 2 kWp and only €200 after — so the state's subsidy and the export economics point the same way, towards a system matched to the house rather than the roof.

What to ask an installer for

• The kWp figure, not just the panel count. Payback maths runs on kWp.
• Their modelled annual generation for your actual roof, with the pitch and orientation they used — then check it against the table above.
• The price broken out: panels, inverter, scaffolding, electrical work, and any battery quoted separately.
• Confirmation they are SEAI-registered, without which the grant does not apply regardless of the quality of the work.
• Whether the payback figure they quote values exported units at the export rate or the import rate.

That last question is the fastest way to find out whether the number in front of you was computed or marketed.