Solar Panel Calculator Ireland:
Cost, Savings & Payback Estimate
Use this Irish solar panel calculator to estimate system cost, annual savings, SEAI grant support, payback period, export income and whether adding a battery could improve your return.
Last reviewed: July 2026. The calculator uses Irish county solar-yield data, current SEAI grant logic, export-rate assumptions and home-solar cost estimates for planning purposes.
What the Solar Panel Calculator Estimates
This page is for homeowners who want a quick solar cost, savings and payback estimate before requesting quotes. The calculator now appears immediately after this summary so you can use the tool first, then read the detailed assumptions and guidance below.
| Calculator output | What it means | Why it matters |
|---|---|---|
| Annual solar generation | Estimated kWh your solar panels could produce each year based on county yield, roof direction, pitch and system size. | Helps estimate how much electricity your home could generate before looking at cost or grants. |
| SEAI grant estimate | Applies current domestic Solar PV grant logic, including the maximum grant available for eligible homes. | Shows your estimated net cost after grant support rather than only the headline installation cost. |
| Annual savings and export income | Separates bill savings from exported electricity income under Clean Export Guarantee rate assumptions. | Shows why using solar power in the home is usually more valuable than exporting every spare unit. |
| Solar payback period | Compares your net cost against estimated annual savings to give an indicative payback period. | Useful for deciding whether to request installer quotes or adjust system size first. |
| Battery comparison | Checks whether adding a battery could improve self-consumption and long-term savings. | Helps decide whether to install solar only, add a battery now, or compare battery costs separately. |
What You Need Before Using the Solar Calculator
You do not need a quote to use the tool. A few basic home details are enough to produce an indicative solar savings and payback estimate.
Your county
County solar-yield data helps estimate annual generation more accurately than a single national average.
Monthly electricity bill
Your bill helps estimate the likely value of self-consuming solar electricity instead of buying from the grid.
Direction and pitch
South-facing roofs usually perform best, but east and west-facing roofs can still produce useful solar output.
Battery or no battery
The tool compares solar-only savings against a battery scenario so you can decide whether storage is worth further research.
How to Interpret Your Solar Calculator Results
The calculator gives an estimate, not a final quote. Use the results to understand the main drivers of solar payback before speaking to installers.
Annual generation
This is the estimated electricity your panels could produce in a typical year. It depends on county yield, system size, roof orientation, pitch and shading.
Self-consumed energy
Solar electricity used in your home usually creates more value than exported electricity because it reduces units you would otherwise buy from the grid.
Export income
Surplus electricity exported to the grid earns a supplier export rate. This supports payback, but your import rate and usage pattern still matter.
Payback period
Payback compares your estimated net installation cost after grant support with your annual savings and export income.
How the Solar Payback Estimate Works
Solar payback is not just the installation price. The calculator combines system cost, grant support, bill savings, export income and battery assumptions to estimate your return.
| Calculation step | What the tool estimates | What to check before relying on it |
|---|---|---|
| 1. System size | Indicative panel capacity based on your home and energy use. | Installer survey, usable roof space, shading and panel layout. |
| 2. Gross installation cost | Estimated solar installation cost before grants. | Brand, inverter type, roof complexity, scaffolding and electrical works. |
| 3. SEAI grant support | Estimated domestic Solar PV grant value if the home and installation are eligible. | Property eligibility, grant history and use of an SEAI-registered installer. |
| 4. Annual savings | Bill savings from using solar power plus export income for surplus electricity. | Your actual day/night usage, tariff, standing charge and export supplier rate. |
| 5. Payback period | Estimated net cost divided by estimated annual savings. | Final quotes, electricity price changes, battery cost and future usage changes. |
Treat the result as a planning estimate. It should help you compare solar-only, solar plus battery and quote scenarios, but a final installer quote is still needed before making a purchase decision.
Next Steps After Using the Calculator
Your result should point you toward the next decision: checking grant eligibility, comparing export income, reviewing battery storage or preparing for installer quotes.
Check SEAI eligibility
Use the grant checker if your calculator result assumes grant support and you want to confirm the main eligibility rules.
Open Grant CheckerCompare export rates
Check current Clean Export Guarantee rates if your payback depends heavily on exporting surplus electricity.
Compare Export RatesReview battery costs
If the battery scenario looks promising, compare battery costs, sizing and payback before requesting quotes.
See Battery CostsCompare solar quotes
Once you understand your likely system size, savings and payback, compare itemised quotes from installers serving your area.
Get Solar Panel QuotesMethodology and Data Sources
The calculator uses simplified assumptions for speed and clarity. The goal is to provide a useful planning estimate, not replace a site survey or final installer quote.
Solar generation data
County-level solar yield estimates are based on the GreenTechReview solar irradiance dataset and PVGIS-SARAH3 methodology. The tool uses county yield, system size, roof orientation and pitch to estimate annual generation. For the full county table, see the Solar Irradiance Ireland page.
SEAI grant calculation
The calculator applies current domestic Solar PV grant logic for eligible Irish homes. Final eligibility depends on the property, previous grant history, application process and using an SEAI-registered installer. Always confirm eligibility before treating a grant estimate as guaranteed.
System cost and VAT assumptions
System cost estimates are indicative and can vary by installer, panel brand, inverter, roof access, scaffolding and electrical works. Domestic solar supply-and-install contracts may qualify for zero-rated VAT, but final treatment should be checked against current Revenue guidance and installer documentation.
Export income and Clean Export Guarantee rates
Export income is estimated using supplier export-rate assumptions. Export rates can change, and the best supplier for export income is not always the best overall electricity plan once import rates and standing charges are included.
Limitations
The estimate does not fully model shading, panel degradation, future electricity price changes, maintenance costs, inverter replacement, complex roofs or all tariff structures. Use it as a starting point before collecting quotes.
Solar Panel Calculator Ireland FAQs
How accurate is this solar panel calculator for Ireland?
The calculator is designed to give a realistic planning estimate using Irish county solar-yield data, grant assumptions, export-rate logic and typical home-solar cost assumptions. It is not a final quote. Shading, roof condition, installation complexity, panel quality and tariff choice can all change the final result.
Does the calculator include the SEAI solar grant?
Yes, the estimate can include domestic SEAI Solar PV grant support where the assumptions indicate eligibility. You should still confirm eligibility using the SEAI guidance and our SEAI Solar Grant Checker before relying on the grant value.
Can I use this as a solar panel cost calculator?
Yes, but treat the cost as an indicative planning range rather than a quote. The tool estimates cost and payback, but installer quotes can vary based on panel brand, inverter choice, roof complexity, scaffolding, battery choice and electrical work.
Does the tool estimate solar payback period?
Yes. The payback estimate compares your net cost after grant support with estimated annual savings from self-consumed solar electricity and export income. It is useful for comparing solar-only and solar-plus-battery scenarios before requesting quotes.
Can it tell me how many solar panels I need?
The tool gives an indicative system size based on your inputs. The exact number of panels depends on panel wattage, roof space, orientation, shading and installer design. A 4kWp system may use roughly 9 to 11 modern panels, depending on the panel rating.
Should I add a battery based on the calculator result?
Use the battery comparison as an early signal, not a final decision. If a battery materially improves annual savings without extending payback too much, compare battery costs and quotes. If it adds too much cost, installing solar first and adding storage later may be a better route.