Can you use a paraffin or portable gas heater indoors in a power cut?

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Only if the heater is made for indoor use, the room is well ventilated and you follow the maker's instructions. The UK Chief Medical Officers say a portable gas heater must be approved for indoor use, and HSE says outdoor and patio heaters are not designed for indoors. Never leave it unattended, turn it off before bed, and fit a carbon monoxide alarm in that room. Never use a camping stove or barbecue indoors.

Why are paraffin and gas heaters a carbon monoxide risk?

Paraffin and bottled-gas heaters burn fuel inside the room. Burning fuel can make carbon monoxide (CO). The NHS lists "gas or paraffin heaters" among the appliances that can make CO if they are faulty, badly fitted or not looked after. HSE explains that CO comes from fuel that doesn't burn completely, and that poor ventilation adds to the risk.

You can't see, smell or taste CO. NI Direct says it is colourless, tasteless and has no smell, so it is hard to notice. That's why an alarm matters.

There is also a fire risk. These heaters have a flame or a very hot surface, and paraffin is a liquid fuel that can spill.

Which heaters must never be used indoors?

Some heaters and cookers are made for outdoors only. Keep these outside, even in a long power cut:

The UK Chief Medical Officers put it simply: be very careful with any heater that is not mains powered. They also say don't light a fire indoors unless you have a proper appliance or fireplace for it. Our guide to flower-pot candle heaters covers another idea that is often shared online.

How do I use a portable gas cabinet heater safely indoors?

The UK CMOs say use only a portable gas heater that is approved for indoor use and runs on gas bottles. Make sure the room is well ventilated and follow all the instructions, because the fumes can be dangerous.

HSE adds:

• Cabinet heaters need a good supply of fresh air to burn properly, so the room must be well ventilated.
• Check the heater has a sensing device. This turns it off if the air quality gets poor.
• Use the correct size and type of gas bottle.
• LPG (bottled gas) appliances in rented homes have the same landlord duties as mains gas, including a yearly check by a Gas Safe registered engineer.

Fire Scotland gives clear steps for the gas bottle:

• Buy a heater with a BSI Kitemark and have it serviced regularly.
• Change the cylinder in the open air. If you can't, open windows and doors.
• Never change a cylinder on a stairway or another escape route.
• Before changing it indoors, put out every flame, including cigarettes and pilot lights.
• Check the empty cylinder's valve is closed before you take it off. Open the new one only when the heater is firmly connected.
• Test for leaks by brushing soapy water on the hose and fittings. If you find a leak, take the heater and cylinder outside and don't use them until the faulty part is replaced.

If you smell gas, follow our smell gas guide, which has the emergency numbers for Great Britain and Northern Ireland.

How do I use a paraffin heater safely?

Fire Scotland's advice:

• Buy a heater with a BSI Kitemark. Never buy a second-hand paraffin heater.
• Use only premium grade paraffin. Never use any other fuel.
• Turn the heater off and let it cool before refilling. Refill outside if you can.
• Fill to just below the maximum line, to leave room for the fuel to expand.
• Wipe up any spill straight away.
• Stand the heater level, on a base that won't burn, away from draughts.
• Ventilate the room it is used in.

The UK CMOs also say use only the fuel recommended for the appliance, and never burn petrol, diesel, lighter fluid, furniture or rubbish.

Can I leave a heater on overnight or when I go out?

No. Fire Scotland says turn off portable heaters before going to bed, and don't leave one on with young children or animals alone in the room. The UK CMOs say never leave a fire, portable heater or generator unattended, and keep a fire extinguisher nearby.

Other fire points from Fire Scotland:

• Don't put a heater too close to furniture, bedding or curtains.
• Don't sit or stand too close: your clothes could catch fire.
• Don't dry or air clothes over a heater.

Do I need a carbon monoxide alarm?

Yes. Fire Scotland says fit a CO detector in any room with a carbon-fuelled appliance, including heaters. The NHS says get one for each room that has a gas, oil, coal or wood appliance.

When you buy one, HSE says check it complies with EN 50291 and has a British or European approval mark, such as a Kitemark. NI Direct says choose an audible alarm. Fit and test it as the maker says. An alarm does not replace servicing: HSE says it is not a substitute for safety checks by a Gas Safe registered engineer.

For more on fitting and testing alarms, see our carbon monoxide at home guide.

Where should spare fuel be stored?

• Paraffin: Fire Scotland says keep no more than 23 litres, and preferably only 9 litres. Store it outside the home in purpose-made containers, away from heat.
• Gas cylinders: store spare ones outside where possible, upright. Don't keep them in basements, near drains, in enclosed spaces, under the stairs, or in a cupboard with electric meters or equipment (Fire Scotland).
• Petrol for a generator has its own rules. See our generator safety guide.

What are the symptoms, and what should I do?

The NHS lists these symptoms of CO poisoning:

• headache
• dizziness
• feeling or being sick
• tiredness and confusion
• shortness of breath

HSE warns the early signs can be mistaken for food poisoning, flu or simple tiredness. A clue is that symptoms ease when you leave the room or the house.

If you think CO is the cause:

1. Turn the heater off if you can.
2. Open doors and windows (HSE) and get everyone outside (NHS).
3. Call NHS 111 for advice. Don't go back in until you've had it.
4. Call 999 if someone has trouble breathing, sudden confusion, chest or muscle pain, weakness, or passes out. Don't drive yourself to A&E.
5. If you think a gas appliance is leaking CO, the NHS says call the National Gas Helpline on 0800 111 999 (free, 24 hours).

Is there a safer way to keep warm in a power cut?

Often, yes. GOV.UK Be Ready says keep warm with blankets and layers, keep the doors of unused rooms closed and draw the curtains. It also says torches are safer than candles. Our guide to keeping warm without power has more ideas, and our winter power cut checklist helps you get ready now.

Heater safety checklist

• The heater is made for indoor use (no patio or camping heaters inside)
• It has a safety mark such as a BSI Kitemark, and has been serviced
• A CO alarm (EN 50291) is fitted in the room and tested
• The room is ventilated
• It is away from curtains, bedding and furniture
• Gas bottles are changed outside, or with windows and doors open
• Paraffin is refilled outside, with the heater off and cool
• It is off before bed and when you leave the room
• Spare fuel is stored outside the home
• Everyone knows the CO symptoms, 111 and 999

General information, not professional advice. Always follow the maker's instructions for your heater, and call 999 in an emergency.

Related guides

• Carbon monoxide at home: signs, alarms and what to do
• Keeping warm without heating: what works, what's safe, and where to get help
• Smell gas? What to do, step by step
• Winter power cut checklist for UK homes

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• Make a household emergency plan

We're an independent UK site, not the government. We check guides against official sources and link to them. In an emergency call 999.

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