The SEAI Solar Electricity Grant is not a flat €1,800. It uses a two-tier per-kWp formula: €700 per kWp for the first 2 kWp, then €200 per kWp for the next 2 kWp, up to a maximum of €1,800. Above 4 kWp, the grant does not increase.
That means a 3 kWp system gets €1,600. A 3.5 kWp system gets €1,700. A 4 kWp system gets the full €1,800. Install 5 kWp or 6 kWp and the grant is still €1,800 — not a cent more.
The table below works through the calculation for every common system size, with panel counts, mid-market install costs in Ireland, and what you actually pay after grant.
The Two-Tier Formula — How the Maths Works
SEAI published the current grant structure on its Solar Electricity Grant scheme page. The structure is straightforward:
- Tier 1: €700 per kWp for the first 2 kWp installed
- Tier 2: €200 per kWp for the next 2 kWp (kWp from 2.01 to 4.00)
- Cap: €1,800 total — reached at exactly 4 kWp
- Above 4 kWp: No additional grant
For any system up to 4 kWp, the formula is:
Grant = (€700 × min(system kWp, 2.0)) + (€200 × max(system kWp − 2.0, 0))
Above 4 kWp, grant = €1,800 regardless of size. Partial kWp values are pro-rated. A 3.5 kWp system:
- €700 × 2.0 = €1,400 (Tier 1)
- €200 × 1.5 = €300 (Tier 2)
- Total: €1,700
A 3.96 kWp system (9 panels at 440W):
- €700 × 2.0 = €1,400 (Tier 1)
- €200 × 1.96 = €392 (Tier 2)
- Total: €1,792
SEAI calculates on the actual system size submitted, to two decimal places. There is no rounding to the nearest whole kWp.
Worked Example: 9 × 440W Panels
Most Irish installers currently quote systems using panels in the 400W–500W range. A common spec across the market in 2026 is a 440W panel — the Jinko Tiger Neo 440W is one example, though equivalent panels from JA Solar, Longi, and others give identical maths.
A 9-panel array at 440W produces:
9 panels × 440W = 3,960W = 3.96 kWp
Grant for a 3.96 kWp system:
- Tier 1: €700 × 2.0 kWp = €1,400
- Tier 2: €200 × 1.96 kWp = €392
- Total grant: €1,792
That is €8 short of the maximum. To reach exactly 4.0 kWp with 440W panels you need 9.09 panels — not possible. The practical choice is 9 panels (3.96 kWp, grant €1,792) or 10 panels (4.40 kWp, grant €1,800 capped). Most installers quote 9 panels as the standard package for a household looking to maximise the grant.
8-Row Grant Calculation Table — 2.0 to 6.0 kWp
Panel counts are calculated at 440W and 500W, rounded to the nearest whole panel. Gross costs are mid-market estimates for a standard pitched roof in Ireland in 2026; exact quotes vary by county, roof type, and installer. Net cost is gross minus SEAI grant.
| System size | Panels @ 440W | Panels @ 500W | Grant calculation | SEAI grant | Avg gross cost | Net after grant |
|---|---|---|---|---|---|---|
| 2.0 kWp | 5 panels | 4 panels | €700 × 2.0 = €1,400 | €1,400 | ~€5,000 | ~€3,600 |
| 2.5 kWp | 6 panels | 5 panels | (€700 × 2.0) + (€200 × 0.5) = €1,400 + €100 | €1,500 | ~€5,750 | ~€4,250 |
| 3.0 kWp | 7 panels | 6 panels | (€700 × 2.0) + (€200 × 1.0) = €1,400 + €200 | €1,600 | ~€6,500 | ~€4,900 |
| 3.5 kWp | 8 panels | 7 panels | (€700 × 2.0) + (€200 × 1.5) = €1,400 + €300 | €1,700 | ~€7,500 | ~€5,800 |
| 4.0 kWp | 9 panels | 8 panels | (€700 × 2.0) + (€200 × 2.0) = €1,400 + €400 | €1,800 | ~€8,500 | ~€6,700 |
| 4.5 kWp | 10 panels | 9 panels | Capped at €1,800 | €1,800 | ~€9,250 | ~€7,450 |
| 5.0 kWp | 11 panels | 10 panels | Capped at €1,800 | €1,800 | ~€10,000 | ~€8,200 |
| 6.0 kWp | 14 panels | 12 panels | Capped at €1,800 | €1,800 | ~€11,500 | ~€9,700 |
Notes: Panel counts are rounded to the nearest whole panel. Gross install costs are mid-market estimates for 2026 — prices vary by location, roof access, inverter spec, and installer. Get at least two quotes before committing. These gross costs already reflect the 0% VAT rate in place since May 2023. You pay the full gross cost to your installer first. SEAI then pays the grant to the bank account you nominate on the application — this is typically your own account, though you can nominate your installer’s account if you prefer. The grant arrives approximately 4–6 weeks after all documentation is submitted to SEAI via mgen.seai.ie.
Why the Grant Caps at 4 kWp — and What That Means for Sizing
SEAI set the 4 kWp ceiling to cover the most common residential install range. A 3–4 bed Irish home using 4,000–5,000 kWh per year typically needs 3–4 kWp to offset meaningful daytime consumption.
Above 4 kWp, there is no further grant. You pay the full marginal cost for extra capacity. Whether that stacks up depends on how you use electricity:
- High daytime use — heat pump, EV charger, home office, larger household — a 5–6 kWp system often pays back the unsubsidised extra panels within 5–8 years through additional generation.
- Low daytime use — working away from home, smaller household — extra panels above 4 kWp export more than they offset. Clean Export Guarantee rates from Irish suppliers currently run 18–32c/kWh (rates vary by supplier and change without notice) versus import rates that have been running 28–38c/kWh, so the arithmetic on the extra capacity is less favourable.
How the 0% VAT Rate Stacks With the Grant
The 0% VAT rate on residential solar PV is separate from the SEAI grant, and both apply to the same installation. The 0% rate has been in place since 1 May 2023 and is a permanent change with no scheduled end date — confirm current status at revenue.ie before committing to a timeline.
The combined effect on a typical 4 kWp installation:
| Item | Amount |
|---|---|
| Pre-VAT installer price (example) | €8,000 |
| If 23% VAT still applied | €9,840 — a €1,840 uplift |
| Under 0% VAT | €8,000 |
| SEAI grant received | €1,800 direct to your bank |
| Effective net cost | €6,200 |
On this example, the combined VAT saving and grant equals €3,640 in total relief. Homeowners who do not qualify for the grant still benefit from the 0% VAT rate. Homeowners who qualify get both.
Reading Your Quote and Checking the Maths Yourself
Your installer quote should show the gross system price and system size in kWp. From the kWp figure, you can check the grant calculation yourself using the formula or the table above.
If the kWp on your quote does not match what the installer quoted verbally, get it corrected before signing. Mismatches between the quote, the Letter of Offer, and the Declaration of Works are one of the more common reasons grant processing stalls.
The grant application goes through mgen.seai.ie and must be submitted before installation begins. The Letter of Offer is valid for eight months — works must be completed and documentation submitted within that window. If the installed system size ends up different from what the Letter of Offer specifies, SEAI will recalculate the grant on submission.
For the full grant guide — eligibility, building age cutoff, the application process step by step — see the SEAI Solar Grant Guide. For the full cost picture including battery options, see the Solar Panels Cost Ireland Guide.
Every installer in the Solar Quotes Ireland network is on the SEAI registered list. There is no fee to homeowners. Fill in one form and we match you with up to four installers covering your county.
Get Free Quotes →Frequently Asked Questions
The SEAI Solar Electricity Grant uses a two-tier formula: €700 per kWp for the first 2 kWp, then €200 per kWp for each additional kWp up to 4 kWp total. The maximum grant is €1,800, reached at exactly 4 kWp. Systems above 4 kWp receive no additional grant. Partial kWp values are pro-rated — a 3.5 kWp system gets (€700 × 2) + (€200 × 1.5) = €1,700.
€1,800. You reach it at 4 kWp. Installing 5 kWp or 6 kWp does not change that figure.
€1,600. The calculation: €700 × 2 kWp (Tier 1) = €1,400, plus €200 × 1 kWp (Tier 2) = €200, totalling €1,600. A typical 3 kWp install in Ireland costs around €6,500 before grant — approximately €4,900 after.
€1,800 — the maximum. The calculation: €700 × 2 kWp (Tier 1) = €1,400, plus €200 × 2 kWp (Tier 2) = €400, totalling €1,800. A typical 4 kWp install costs around €8,500 before grant — approximately €6,700 after.
No. The grant is capped at €1,800 regardless of system size. The additional capacity above 4 kWp is entirely at your own cost. Whether it pays back depends on your daytime electricity use — high users (heat pump, EV charger) often justify going above 4 kWp; low daytime users less so.
To the bank account you nominate on the SEAI application — usually your own. You pay the full gross install cost to your installer upfront. Once all documentation is submitted through mgen.seai.ie and approved, SEAI pays the grant to that nominated account. Some installers offer to deduct the grant from your invoice and have you nominate their account instead — that arrangement is between you and the installer. Payment typically arrives 4–6 weeks after the final document upload.
Yes. The two are fully independent and stackable. The 0% rate applies to all residential solar PV installations regardless of whether you claim the grant. On a typical 4 kWp install, the combined value of the VAT saving (approximately €1,840 versus the full 23% rate) and the €1,800 grant comes to around €3,640 in total relief.
Yes, the grant still applies but remains capped at €1,800. On a single-phase supply, the NC6 microgeneration notification covers systems up to approximately 6 kW. Above that, you move into mini-generation territory and need to submit an NC7 form to ESB Networks — a more involved connection process. For most residential properties, 6 kWp is the practical upper limit on a standard single-phase supply.
Published: 18 May 2026. Updated: 19 May 2026. Author: Neil Russell. Fact-checked against seai.ie, citizensinformation.ie, revenue.ie, esbnetworks.ie, and cru.ie live sources.