Experts are warning that the coming heatwave is turning a string of everyday household items into a serious fire risk, with fire services saying that a sunny windowsill can act like a magnifying glass
11:50, 22 Jun 2026Updated 11:52, 22 Jun 2026
Homes can quickly become hot and stuffy on a hot day but there is a easy way to cool down without needing to plug anything in
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With Met Éireann issuing a heat warning for the entire country this week, homeowners are being issued a serious warning about the increased risk of fire hazards at home.
A Status Yellow High Temperature warning has been announced for every county in Ireland ahead of boiling temperatures that are expected to reach over 30 degrees.
The warning will come into place from tomorrow afternoon, Tuesday, June 23rd, starting at 12 pm, and will last until Friday, June 26th, at 9 am.
These temperatures can turn a string of everyday household items into a serious fire risk, with fire services warning that a sunny windowsill can act like a magnifying glass
The risk from a hot windowsill comes in two forms: some items focus the sun’s rays like a magnifying glass and set curtains or furniture alight, while others simply overheat until they leak, burst or catch fire.
Here are the five things to get off your windowsill this week.
Vapes and lithium battery devices
This is the big one, because a huge number of people in Ireland now vape, and that is before you count the phones, earbuds, headphones, laptops, power banks and smartwatches in every home. They all run on lithium-ion batteries, and a sunny windowsill is one of the worst places to leave any of them.
Sustained high temperatures can create a violent chain reaction where the cell overheats and catches fire or explodes, and these fires are notoriously hard to put out. Lithium batteries pack a huge amount of energy into a tiny space, and if that energy is released uncontrollably, a fire or explosion can follow.
Shane Margereson, spokesperson for vape specialists ecigone, explained: “People think of this as a vaping issue, but it is really a lithium battery issue. A vape is essentially a small battery with a flammable liquid attached, so leaving one in direct sun on a hot windowsill is asking for trouble, and the same goes for your power bank, your earphones or a phone left charging on the ledge.
“Lithium cells simply do not cope with sustained heat. Once a damaged or overheated cell starts to fail, it can go from completely normal to venting flames in seconds. Our advice this heatwave is simple: never charge or store anything with a battery in direct sunlight, and if a device looks swollen, smells odd or feels hot, stop using it straight away.”
Mirrors
A vanity or magnifying mirror on a sunny sill is one of the most common causes of these freak fires. Its curved surface focuses sunlight onto one intense point that can scorch and ignite curtains, furniture or paperwork.
Glass ornaments, paperweights and a glass of water
It is not just mirrors. Any clear glass that bends or reflects light carries the same risk: decorative ornaments, crystal, paperweights, even a forgotten glass of water or a fish bowl.
Aerosol cans
Deodorant, dry shampoo, air freshener and hairspray are all sealed under pressure, and we get through a staggering number of them.
Nearly every can carries a warning not to store it above 50C, a level a sunlit windowsill easily beats in this weather. Speaking to Ideal Home, Danny Stalman of Plan-It Windows said: “Aerosols and flammable items on a windowsill are a significant hazard, especially during warmer seasons.” He added: “The sunlight can heat these items to dangerous levels, leading to potential explosions.”
Candles, matches and lighters
We are a nation of candle lovers, but a windowsill is the wrong home for them. A candle in direct sun can soften, warp and burn unevenly, but the real danger is fire, especially next to flammable curtains or blinds.
A disposable lighter is also full of pressurised, flammable gas that can expand and crack its casing in the heat. Window expert Allan Reid, of Art Windows and Doors, told Ideal Home: “Candles, matches or lighters pose a fire hazard on a windowsill, especially near flammable curtains.”
What to do during the heatwave
Keep vapes, power banks and other battery devices out of direct sunlight, and never charge them on a windowsill. Move mirrors, glass ornaments, paperweights and glasses of water away from the window. Store aerosols, candles and lighters somewhere cool and shaded.
And check your smoke alarms, with research showing that you are around nine times more likely to die in a fire without a working one.
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