Do flower-pot candle heaters work? An honest answer

The short answer

1. They don't heat a room. A pot can't make more heat than the candles under it. It just holds the heat and lets it out more slowly.
2. UK fire services advise against them. One collapsed and set fire to a flat in Derby in 2022.
3. Use something else. Warm clothing, blankets and sleeping bags. Torches, not candles, for light.

Why the pot can't add heat

The idea is that tealights under an upturned terracotta pot "trap" and "boost" the heat. The experts disagree:

• A thermodynamics professor at Imperial College London told the Big Issue that the pot adds no energy. It only slows down how fast heat is lost.
• Two professors told AAP FactCheck (January 2024) the same: the only energy going in is the candle flame. The pot warms up and gives off heat you can feel close by, but the total heat stays the same.
• One of them, Professor Joan Vaccaro, put a typical candle at about 80 watts of heat in total. The other, an MIT heat transfer expert, said a candle doesn't give off enough energy to heat a normal room.

We couldn't find an official UK figure for how much heat a tealight gives, so we haven't given one.

So why does it feel warm? The pot gets hot, and you can feel that heat if you sit right next to it. That's the candles' own heat, not extra heat.

What UK fire services say

We tried to open the fire services' own news pages on 3 November 2026 but couldn't reach them, so the table uses news reports of what each service said.

The real risks

• Fire. The Derby fire started when the heater collapsed and melted wax caught fire.
• Burns. The pot gets hot enough to burn skin.
• Carbon monoxide. The NHS lists faulty boilers, gas and paraffin heaters, fires, generators, and barbecues or camping stoves used indoors as causes. It doesn't list candles, but the Scottish Fire and Rescue Service warned that homemade heaters carry a carbon monoxide risk too. CO has no colour or smell. Signs include headache, dizziness, feeling sick, tiredness and confusion.

If you think someone has carbon monoxide poisoning, the NHS says stop using the appliance if you can, go outside, and call NHS 111. Call 999 if someone has trouble breathing, sudden confusion or passes out. If you think a gas appliance is leaking, call the National Gas Helpline on 0800 111 999.

If you do use candles

GOV.UK Be Ready says torches are safer than candles. If you still use them, its fires in the home page says:

• Put candles in a proper holder, away from anything that can catch fire, such as curtains.
• Put them out properly before you go to bed.
• Fit smoke alarms on every level and test them at least once a month.
• Plan and practise an escape route.

Avon Fire and Rescue Service adds: never leave a lit candle alone, don't move it once it's lit, and don't burn several close together.

Safer ways to keep warm

GOV.UK Be Ready says homes can get cold very quickly when the heating goes off. Its checklist lists:

• Blankets and sleeping bags
• Warm clothing
• A torch and spare batteries, instead of candles

The NHS says never use a barbecue or camping stove indoors.

Our keeping warm without power guide has the full step-by-step list, and our carbon monoxide guide covers alarms.

Last checked

Checked against GOV.UK Be Ready, the NHS, AAP FactCheck and news reports of UK fire service warnings on 3 November 2026. This is general information, not professional advice. If there's a fire, get out, stay out and call 999.

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
• Home fire escape plan: how to make one your whole household knows
• Heat alarm or smoke alarm? Which alarms your home needs

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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