Power Cut Readiness | Practical UK Household Guide

A power cut is often more manageable when you have thought through lighting, communications, safe food and keeping warm before it occurs. You do not need an expensive power station to start preparing.

KNOW YOUR LOAD BEFORE YOU BUY

Estimate your essential backup power

Check the running watts (W) shown on your own device or manufacturer information. Estimate how many hours each day you would actually run it. This is a rough energy-budget calculation, not a guarantee that any power station, generator or inverter will operate it.

1. Your essential devices

Start with the devices that really matter. Enter the quantity, running watts and daily hours for each. Do not enter a manufacturer's maximum wattage as if it were a measured average. For fridges and other cycling loads, seek their actual average consumption; medical-critical equipment requires a verified continuity plan from its provider.

2. How long and what power do you have?

Days you want to cover Existing battery's rated capacity (Wh) Illustrative usable fraction of rated capacity

Rated battery capacity is not a promised usable output. Real efficiency, ageing, temperature, inverter losses and battery protection vary. Enter a maker-verified usable capacity when available, and choose the 100% option only when your entry is already a verified usable figure.

Enter the actual power requirements for at least one device.

Results will appear here after calculation.

Important power and safety limitations

W (watts) describes running demand; Wh (watt-hours) describes energy over time. Some appliances need a far higher startup surge than their running wattage. Outlet and inverter limits, AC versus DC connections, battery compatibility and charging time must all be checked separately. These figures do not size a home electrical installation.

Do not rely on this calculator for medical equipment, heating, refrigeration safety or life-sustaining needs. Speak to the equipment provider or competent installer and your electricity network about an appropriate backup plan.

Never operate a fuel-powered generator indoors, in a garage or near open windows and doors. Never backfeed your home wiring; use a qualified professional for any permanent installation. During a power cut, follow official instructions and use torches rather than candles where possible.

UK Government: power cuts · HSENI: generator safety · Long-term power planning

Before an outage

Identify rechargeable torches, charged phone power banks and a battery/wind-up radio; learn how to use them.
Write important phone numbers on paper and know where they are kept.
Check how people relying on powered medical equipment should seek support from their provider and electricity network.
Keep appropriate ready-to-eat food, safe drinking water and suitable warm layers available.
Check smoke and carbon monoxide alarms and safe ventilation.

During a power cut

Use torches rather than candles wherever possible. Keep fridge and freezer doors closed.
Do not use camping stoves, barbecues, petrol generators or other fuel-burning equipment inside a home or enclosed space. Carbon monoxide can kill.
Check vulnerable household members and neighbours where safe.
For power-cut reports, use the published emergency contact for your local electricity distribution network operator. Reporting numbers vary across the UK. See the UK Government power-cut guidance for household safety steps.
If anyone is in immediate danger, call 999.

Do not assume food remains safe

The Food Standards Agency explains that an unopened fridge typically stays cold for up to around four hours; a full closed freezer may keep food frozen for up to 48 hours, or about 24 hours if half-full. These are estimates—not guarantees. Appliance and room temperatures and how often the doors are opened matter. Follow official food safety advice rather than judging solely by appearance or smell.

What equipment is genuinely useful?

Often already available: blankets, warm clothing, mobile charging leads, working torches. Ordinary retail: safe drinking water and familiar ready-to-eat food. Specialist if justified: a suitable certified backup battery or professional power installation for a demonstrated need; calculate actual load and manufacturer compatibility first.

Plan your next step

Count food you could use · Print your household plan · Explore longer-term power and heating planning.

Official references

UK Government Prepare campaign · Food Standards Agency: power cuts and food.

Guide reviewed 14 October 2026. General planning guidance—not a guarantee of safety. Check current official advice and the circumstances of your household.