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RetrofitReady is a free information service. We are not affiliated with SEAI or any government body. Grant figures are indicative only and may change without notice. Always verify current rates and eligibility at seai.ie before signing any contract or starting any work. We do not endorse or guarantee any contractor listed on this site.

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Battery Sizing Calculator

Find the right battery size for your solar system based on your usage and backup needs.

Average Irish home: 11.5 kWh/day

Battery recommendation

Recommended size

7.5 kWh

Estimated cost

€5,250

Annual saving

€818/yr

Payback period

6.4 years

No SEAI grant currently available for battery storage. 0% VAT applies.

When are you thinking of doing this?

We'll only match you to contractors when you're ready.

Next steps

Solar calculator →Check if solar panels suit your homeSolar sizing calculator →Find the right system sizeFind solar installers →SEAI-registered solar contractors near youCheck your home →Full assessment with all grants
Official SEAI Resource — always verify grant details directly with SEAI before applying.

Last verified: 2026-06-01