How Long Will It Run

Medical equipment in a power cut

If someone at home depends on powered equipment, a power cut is more than an inconvenience. This page covers the official help first, then the batteries and small things that fill the gap, with runtimes from this site's calculator. It is general information, not medical advice.

In the US? See the US edition.

Know this first

Join the Priority Services Register

The Priority Services Register is free and run by your electricity network operator and supplier. People on it who use medical equipment get advance warning of planned cuts, contact during unplanned ones, and in some areas practical help such as hot food or a generator. Sign up through your supplier or by calling 105.

Oxygen

The NHS home oxygen service provides backup cylinders for a power cut; ask your supplier how many you have and how long they last. An oxygen concentrator draws a few hundred watts, so a portable power station runs one for hours rather than days: see the table below. Never change a prescribed flow rate to make a battery last longer.

CPAP

A CPAP draws far less than most people expect, especially with the humidifier off and a DC cable instead of the mains plug. That puts a night or two within reach of a station of about 500 Wh, and more with the DC cable. Details in CPAP on battery power.

Insulin

Most insulin in use can be kept out of the fridge for about four weeks, at up to 25 °C or 30 °C depending on the brand, as the patient leaflet in the box says (leaflets are also on the eMC). Ask your pharmacist or diabetes team if unsure. A power cut in a British winter is rarely the problem; a heatwave cut is. Keep spare insulin in the fridge shut, and never let it freeze.

Keeping the equipment going

Ask the supplier before connecting anything to medical equipment.

DC power cable for the CPAP

Running a CPAP straight from a 12 V socket skips the inverter and makes any battery last much longer.

Look for: A cable made for your exact machine; ask the equipment supplier which one before buying.

Power bank, 20,000 mAh

Keeps a phone going for days if you use it sparingly.

Look for: Capacity in watt-hours as well as mAh (about 74 Wh for 20,000 mAh), USB-C in and out, and keep it charged.

Insulin and medicines

For a summer cut or a long one.

Insulin cooling wallet

Evaporative cooling wallets keep insulin pens below room temperature for days with no fridge and no ice, which matters most in a summer outage.

Look for: A size that fits the pens or vials you actually use, and instructions on how long one soak lasts.

Fridge and freezer thermometers

The only way to know whether the food stayed cold enough, rather than guessing from the clock.

Look for: One for each appliance, readable without opening the door for long.

Light and contact

So nobody is fumbling for tubing or pens in the dark.

Plug-in power failure lights

They live in a socket as a night light, charge themselves, and switch on the moment the mains goes off, so you are never hunting for a torch in the dark.

Look for: A built-in battery you can pull out and carry as a torch, and a UK three-pin plug if you are in the UK.

Head torch

Both hands free for the fuse box, the stairs and the kettle you cannot use.

Look for: USB-C charging or common AA batteries, and a red-light mode that does not dazzle everyone else.

Mini UPS for the router

Home phones now run through the broadband router, so when it goes off in a power cut the landline goes with it. A small battery box keeps the router, and the phone plugged into it, working.

Look for: DC outputs that match the voltage printed on your router's power adapter (usually 12 V), enough of them for the fibre box too if you have one, and a capacity in watt-hours.

What a power station keeps running

The kit above keeps people comfortable. A portable power station keeps things running. This is what a 1,056 Wh Anker SOLIX C1000 manages for each load on its own, from full.

LoadAlone, from full
CPAP (no humidifier)18 h 43 min
CPAP with heated humidifier12 h 23 min
BiPAP / VPAP13 h 42 min
Oxygen concentrator (5 L/min)2 h 8 min
Nebuliser5 h 26 min
Medication fridge (insulin)31 h 19 min

These are modelled averages from the same catalogue as the rest of the site, not measurements of your machine. Check the watts on your own equipment's label, and use the calculator to size a station for it. Compare stations in the buying guide.

Checklist to print

  • On the Priority Services Register with your network operator
  • Equipment supplier's power cut advice written down by the equipment
  • Backup oxygen cylinders, if you use oxygen
  • Battery or power station charged, and tested on the equipment
  • Spare insulin and medicines, and a cooling wallet
  • A charged mobile phone, and 105 and the supplier's number written down
  • Power failure lights by the bed and the equipment

Before winter

  1. Join the Priority Services Register, and check your details are current if you already have.
  2. Ask your equipment supplier what to do in a power cut, and whether a DC cable or battery is approved for your machine.
  3. Test the backup: run the equipment from the battery for a whole night while the power is on.
  4. Tell a neighbour or relative who can check on you if the power goes.

Sources

Amazon links on this page are affiliate links; the site may earn a commission at no extra cost to you. They are searches for a type of product, not endorsements of a particular model, and nothing here has been tested hands-on. Prices and stock change constantly.