Home Battery Sizer
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Power Cut Backup Calculator (Ireland)
Storm Éowyn turned outage backup into a mainstream Irish concern. This calculator lets you pick what you need to keep running in a power cut — fridge, freezer, broadband, oil-boiler pump, well pump, medical devices — and works out exactly what size portable power station you need and how long it will last on a charge.
Reviewed Jul 23, 2026
The tool
Open the tool full-screen ↗Use it right here — nothing is saved, and there’s no sign-up.
This tool may link to relevant products and services to keep it free. Affiliate links are marked and are placeholders during this early phase — see our affiliate disclosure
What to know
Sizing a power station is two questions: how much power your devices draw at once (watts), and how much energy you need over the outage (watt-hours). A fridge and broadband router sip power; a well pump or an oil-boiler pump spike hard when they start. Getting both numbers right is the difference between a unit that carries you through a long cut and one that trips on the first pump start.
The tool includes the Irish specifics that generic calculators miss — well-pump and oil-boiler-pump presets for rural homes, short-term essentials presets (fridge, freezer, broadband, medical devices), and winter-yield solar recharge if you want to top up between cuts. It ends by recommending a capacity class and, if you’re weighing whole-home resilience, links across to the home battery sizer.
How this tool works
No sign-up, nothing saved — here is what it does with your answers.
- Tick the appliances and devices you need to keep running, and for how long.
- The tool adds up peak power and total energy, allowing for spikes from pumps and motors.
- You get a recommended power-station size and a realistic runtime, with optional solar recharge.
Frequently asked questions
What size power station do I need for a power cut?
Enough to cover the combined running power of your essentials plus the surge when pumps and motors start, and enough stored energy for the outage length. The tool sizes both from your picks.
Can a power station run my oil boiler or well pump?
Usually yes, if it’s sized for the pump’s start-up surge — which is much higher than its running power. The calculator includes Irish well-pump and oil-boiler-pump presets for exactly this.
Power station or home battery?
A portable power station is grab-and-go for essentials; a home battery with backup can carry more of the house but costs more and is fixed. The home battery sizer helps compare.
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