What solar panels do on an Irish roof
Solar panels make electricity out of daylight. They work under Irish cloud, just not as hard as they do on a clear day in June.
What goes on the roof
Panels on the roof, an inverter on a wall inside, and a day's work. There is nothing to maintain, nothing to feed and nothing to hear. A kilowatt of panels is three or four of them, and a typical house takes three or four kilowatts.
The panels make direct current when light falls on them; the inverter turns that into the kind of electricity the sockets use. Whatever the house is using at that moment is served first. Whatever is left goes out to the grid.
That last sentence is the whole design problem. Panels produce at midday. Houses use power at eight in the morning and seven in the evening. Everything you can do to move usage into the middle of the day — the immersion, the washing machine, an electric car, a heat pump running its hot water cycle — turns exported units into units you didn't have to buy.
Is it right for a house like yours?
Your cert may say B2 — that's a B on the new scale.
A heat pump runs on electricity. Pick "Heat pump" if you have one.
A 1970s–80s detached house on oil, rated CEnergy rating C
- Grants you’d get
- €10,300
- It costs about
- €19,000
- You pay
- €5,000 – €8,900
- Saves you each year
- about €760
- Pays for itself in
- about 15 years
The commonest home on file — 24,045 like it. Change an answer above for yours.
Modelled, not observed payments. Middle case €8,930; a quarter of these homes are over €13,884. Repaid in 15.1–16.7 years. Confidence 0.9.
Show what’s included
This is the job list that suits most homes like yours (2 in 10). The money above is the middle of every route we priced, so it will not add up to this list exactly.
Solar panels — on the roof, one day, no disruption. Cuts the electricity bill, and pairs well with a heat pump.
2.4 kWp ≈ 2,040 kWh/yr. Cost €9,400 · grant up to €1,800 · you pay €7,600.
Costs about €10,700 · grant €1,800 · you pay €8,900
The paperwork — assessment first, grant approval, then the work, then a new energy cert, then the grant is paid. A One-Stop-Shop does all of it and takes the grant off the bill.
Order is mandatory — work started before approval is not eligible. Energy cert €276, assessment grant €350 through a One-Stop-Shop. Typically 3–6 months end to end (estimate).
Costs about €280 · grant €350 · the grant covers it
Compared with buying every unit from the grid
| Grid electricity | Your own panels | |
|---|---|---|
| What a unit costs | 34.4c for direct electric heat | nothing, once the system is paid for |
| When you get it | any time | daylight, mostly the middle of the day |
| Across the year | flat | about 75% of it between May and September |
| In cloud | unaffected | still generating, below rated output |
| What it does to the bill | — | cuts the units you buy, if you use them as they're made |
| Kit that wears out | none of yours | the inverter, before the panels |
| Time to fit | — | about a day, no rooms cleared |
Grant €700 per kWp to 2 kWp, then €200 per kWp to 4 kWp, capped at €1,800; paid pro rata, e.g. €1,500 for a 2.5 kWp system. SEAI median cost €9,400 for a semi-detached, €10,730 detached. Home must have an MPRN and have been built and occupied before 2021; not available where PV was previously grant-aided at the same MPRN; 8 months from grant offer to completion. Grant steps and conditions read on seai.ie 8 September 2026; cap amount verified 2026-09-07.
Where the saving comes from
Every other upgrade on this site reduces the heat a house loses. Solar panels don't touch the heat at all — they cut the number of units you buy. That's a different kind of saving, and it behaves differently: it doesn't depend on how cold the winter is, it doesn't care how good the walls are, and it is worth exactly what a unit of electricity costs on the day you don't buy it.
It's also why panels and a heat pump suit each other. A heat pump turns the house's heating bill into an electricity bill, and panels take a bite out of electricity bills. Heat from a heat pump costs about 9.8c a unit against 34.4c for plug-in electric heat; the panels then chip away at what's left.
A 1970s–80s detached house on oil, rated C — for the 24,045 homes in that group the cheapest grant-eligible route to a B includes solar panels, and it repays in about 15 years at the modelled saving. That is slower than the insulation measures, because the grant covers a smaller share of the cost. detached|1970-1989|C|oil: cost p50 €19,019, grant €10,300, net p25–p75 €5,019–€13,884, saving €761/yr, payback 7.7–16.7 yrs, n=24,045, confidence 0.9
Common questions
- Does solar work in Irish weather?
- Yes. Panels run on daylight, not warmth, so cloud reduces the output rather than stopping it — SEAI say a system still works on an overcast day, below its rated output. The real constraint is the season. About 75% of the year's generation happens between May and September, so the panels give least in the months you use most.
- How much of my electricity will it cover?
- SEAI's worked example is a system of about 20 square metres, roughly 3 kilowatts, generating around 2,600 units a year — over 40% of what an average Irish home uses. Covering that much of the bill is a different matter, because the panels make their power in the middle of the day and most houses use theirs in the evening.
- Do I need planning permission?
- Usually not, if the panels stay 50 cm in from the edge of the roof and don't go forward of the front wall of the house. Panels on a wall are not exempt, free-standing panels in the garden have their own size limits, and a house in an architectural conservation area needs a call to the council first.
Where to next
Where this comes from
Last checked 2026-09-08.