Heat pump in a power cut

This guide is for homes heated by an air source or ground source heat pump, and for all-electric homes. It explains what happens to your heating and hot water when the power goes, and the simple things that help you stay warm until it's back.

The short answer

A heat pump runs on electricity, so it stops when the power goes. Your home holds some of its warmth for a while, and you can help it hold on to that warmth by closing doors and curtains and keeping to one room. When the power comes back, the heat pump should start up again on its own.

Use the checker above to see what else in your home stops in a power cut.

In the first hour

1. Check whether it's just your home. Look at your fuse box for a tripped switch, and see if your neighbours' lights are off too.
2. If it isn't a tripped switch, call 105 to report it or get an update. It puts you through to your local network operator. See who to call in a power cut.
3. Switch heaters and other appliances off at the wall, so they don't all come back on at once. Leave one light switched on so you know when the power's back.
4. Use torches or battery lanterns, not candles.

Keeping the heat in

• Close internal doors to keep warm air where you are.
• Close curtains and blinds, especially once it gets dark.
• Choose one room to keep warm and spend your time there.

Keeping yourself warm

• Wear layers.
• Use blankets, a hat and warm socks.
• Have hot drinks and hot water bottles if you filled a flask before the cut. When a storm or cold spell is forecast, filling a vacuum flask with hot water is a simple way to get ready.

Never use a gas oven, gas hob, camping stove or barbecue to heat a room. See the carbon monoxide advice in our boiler guide.

Hot water

If you have a hot water cylinder, the water in it stays warm for a while after the power goes, but it won't be heated again until the power returns. An electric immersion heater stops too. Use stored hot water carefully, and keep some of your stored water for washing.

If someone at home needs extra help

Older people, babies and anyone who is unwell may need extra help to keep warm. Keep them in the warm room and check on them often.

If someone at home relies on medical equipment or care, join the Priority Services Register. It's free, and it tells your network operator to give your household extra help in a power cut. Talk to the equipment supplier about a backup plan.

Pets need a warm room and fresh water too.

Is backup power worth it?

A power bank is enough to keep phones charged. It won't run a heat pump, heating controls or anything else that plugs into a mains socket.

If you want to keep something bigger going, a portable power station may help. We don't size power stations or work out how long they'd run something. Our sister site covers that: read Ferncharge's guide to power stations for power cuts.

Never connect a generator or power station to your home wiring yourself. That needs a qualified electrician with the right switchgear.

Our backup power guide explains the difference between a power bank and a power station.

When the power comes back

• Your heat pump should restart on its own.
• Switch appliances back on a few at a time.
• If the heat pump shows a fault or doesn't restart, check the installer's or maker's guidance, or contact your installer.

When to get help

• If anyone is in immediate danger, call 999.
• If you're worried about someone's health in the cold, call NHS 111.
• For updates on the power cut, call 105 or check your network operator's website.
• For a heat pump fault, contact your installer.

This guide gives general advice. It can't tell you how your own heat pump or home will behave, so check your installer's guidance for your system.

FAQs

Will my heat pump work in a power cut?

No. A heat pump needs electricity, so it stops when the power goes. It should restart when the power comes back.

How can I keep warm without my heat pump?

Keep to one room, close doors and curtains, wear layers and use blankets. Fill a flask with hot water when a storm or cold spell is forecast.

Can a power station run a heat pump?

We don't work out what a power station can run. Our sister site Ferncharge compares power stations and checks how long one would run your devices. Never connect one to your home wiring yourself.

Will I still have hot water?

If you have a hot water cylinder, the water already in it stays warm for a while, but it won't be heated again until the power is back.

Should I make a plan for power cuts?

Yes. Our household power cut plan asks how your home is heated and gives you a one-page plan to print.