☀️ Solar Payback Calculator
Will solar panels pay for themselves?
Solar quotes come with a payback figure attached and it is almost always calculated optimistically — usually by assuming you use most of what you generate. You probably do not. This lets you set that number yourself and shows what it does to the answer.
Figures reviewed September 2026. Free, no signup, nothing stored on our servers.
What this means
Payback is the point at which the electricity you did not buy, plus the export income, adds up to what the system cost. Under about eight years is a strong case; beyond about fifteen the system is competing with its own warranty period.
Self-consumption decides this. A kilowatt-hour you use in the house is worth the full retail price you avoided paying — around 35 cent. The same kilowatt-hour exported earns the Clean Export Guarantee rate, usually a little over half that. A household where everyone is out from eight to six exports most of a summer day’s generation, and that halves the return.
Irish yield is lower than the figures used in most marketing material. Roughly 850 kilowatt-hours per kilowatt-peak per year is a realistic planning figure for a well-oriented Irish roof — a southern European number would be half as much again, and using it makes the payback look years shorter than it will be.
What affects the result
- Self-consumption — the single largest factor, and the one quotes are most optimistic about.
- Orientation and shading. A north-facing roof generates around 60% of what a south-facing one does.
- The export rate your supplier pays, which varies and is not regulated to a fixed figure.
- Electricity price inflation. The more prices rise, the more the panels are worth.
- Whether a battery is included. It raises self-consumption but is a large cost with no grant.
- Whether the SEAI grant applies — it is limited to homes built and occupied before 2021, subject to SEAI conditions.
Will solar panels pay for themselves?
How to raise self-consumption without a battery
An immersion diverter sends surplus generation to the hot water cylinder instead of the grid, and costs a fraction of a battery. Running the dishwasher, washing machine and any EV charging during daylight does the same thing for free. Both move units from the export rate to the retail rate, which is where the value is.
Getting a quote you can compare
Solar quotes vary widely for the same system size. Get three, on the same specification, and run each through the quote checker. Ask what yield figure the installer used for their payback claim — if it is materially above 900 kWh per kWp for an Irish roof, the payback they quoted is optimistic.
Other things to do first
Solar reduces the electricity bill; it does nothing for heating. If the house is poorly insulated, the home energy upgrade tool ranks the measures by payback and insulation almost always comes first. And switching supplier is free and takes ten minutes.
Important assumptions
Every figure on this page rests on these. Where one does not match your situation, the answer moves — sometimes a great deal.
- Annual yield defaults to 850 kWh per kWp for a south-facing unshaded Irish roof, adjusted by the orientation factor you choose.
- SEAI solar grant calculated at the published rates per kWp, capped at the published maximum. Eligibility conditions are SEAI's, not ours — check them before budgeting on it.
- Panels degrade at the rate you set, defaulting to 0.5% a year.
- Export income is paid at a flat rate with no inflation applied, which is conservative.
- No inverter replacement is costed. Most inverters are expected to need replacing once in a 25-year life, typically a four-figure sum.
- No maintenance, cleaning or insurance costs are included.
- Domestic solar installations have been zero-rated for VAT in Ireland since May 2023, so the quoted price is treated as VAT-free.
Official sources
Where this tool applies a published rule, this is where the rule comes from. Check the source before acting on anything that matters.
- SEAI — Solar Electricity Grant
Current grant amounts per kWp, the maximum, and the eligibility conditions including the property age requirement.
- CRU — Microgeneration and the Clean Export Guarantee
The regulator's framework requiring suppliers to pay for exported electricity, and what that obliges them to do.
- SEAI — Solar PV information and yield
Official Irish guidance on what a domestic solar system generates and how to size one.
Common questions
Is solar worth it in Ireland?
For a household that uses a reasonable share of what it generates, usually yes — typical paybacks land in the seven to twelve year range with the grant applied, against a panel warranty measured in decades. For a household out all day with no battery and no immersion diverter, the case is much weaker because most generation is exported at roughly half its value.
How much electricity does a 4kW solar system generate in Ireland?
Around 3,400 kilowatt-hours a year on a well-oriented, unshaded roof, using a planning figure of about 850 kWh per kWp. Orientation and shading reduce that — an east or west facing roof generates roughly 80% of a south-facing one.
Do I get paid for electricity I export?
Yes. Under the Clean Export Guarantee, suppliers must pay microgenerators for electricity exported to the grid. The rate varies by supplier and is not fixed by the regulator, so it is worth comparing — and worth re-checking when you switch supplier.
Is a battery worth adding?
It depends entirely on how much it raises your self-consumption and what it costs. A battery earns the difference between the retail price and the export rate on every unit it shifts, which is a modest margin, so batteries usually have a longer payback than the panels themselves. There is no SEAI grant for battery storage.
What is the SEAI solar grant worth?
It is paid per kilowatt-peak installed up to a published maximum, and is only available for homes built and occupied before 2021. The calculator applies the current published rates. SEAI sets the conditions, including the requirement to use a registered installer.
What to check next
What grant can I get for solar?
Current SEAI grant amounts for solar PV and what they leave you to pay.
SEAI Solar GrantNewWhich energy upgrade is worth doing first?
Attic, walls, windows, heating and solar ranked by estimated saving against cost.
Home Energy UpgradePopularAm I paying too much for electricity?
Compare Irish electricity and gas tariffs on net first-year cost, not headline rate.
Energy Switch ComparisonNewWould a heat pump cost me less to run?
Your current heating cost against a heat pump at realistic Irish efficiencies and prices.
Heat Pump SavingsNext steps across CheckIreland
Picked for what you just worked out — not a list of everything we make.
- Insulation usually pays back fasterSolar cuts the electricity bill. Insulation cuts the heating bill, for a fraction of the cost.
- Check your export rateThe Clean Export Guarantee rate varies by supplier and changes when you switch.
- Compare the installer quotesSolar quotes vary widely for the same system. Three, on the same specification.
CheckIreland is independent and is not affiliated with the Irish Government or any public body. This tool is general information built on published rules and typical costs — it is not financial, tax or legal advice, and it does not account for your individual circumstances. Confirm anything that matters with the relevant body or a qualified adviser before acting on it.