The windowsills in my kitchen often have items lined up on them, especially our empty glass milk bottles. But fire safety experts warn that storing glass in this spot can pose an alarming fire risk.
Especially in the summer months when the sun’s power is more keenly felt, light entering your bottle and exiting concentrated on fabric such as curtains, upholstery or even paper towels could spark a fire in your home.
Here, our experts explain the fire risks and what to do instead with glass jars and bottles to keep your home's windowsills from sparking an inferno any time of year.
Keeping glass and reflective kitchen items stored in a cabinet or a chic countertop storage bin from Wayfair will stop sunlight from traveling through and posing a risk.
Former firefighter and managing director of Fire Evacuation Services, John Duthart, explains, ‘Incidents involving sunlight passing through glass objects are not as rare as people might think, with many fires in the past decade caused by the sun's rays.
‘A simple glass item like a condiment jar left on a windowsill can focus sunlight onto nearby surfaces like blinds or fabrics and lead to a devastating fire under certain conditions.’
Why Glass Objects Can Easily Cause Fires Fast
Glass objects and reflective surfaces can act like a magnifying glass, concentrating the sun’s rays into a focused hot spot. If that heat is directed onto flammable materials for long enough, it can cause smouldering, which may then develop into a full fire.
John adds, ‘In strong direct sunlight, nearby materials can begin to heat up within minutes. The exact timing depends on the strength of the sunlight, the type of glass involved and how close combustible items are to the focused light.’
The Household Materials That Pose the Most Risk
Curtains, bedding, paper, cardboard, clothing and soft furnishings are among the most vulnerable because they can heat up and ignite more easily once sunlight is concentrated onto one small area.
John explains that proximity plays a part. He says, ‘A mirror, glass ornament or jar placed on a windowsill may only need to focus sunlight a short distance onto nearby curtains or furniture to create dangerous heat build-up.’
Reduce this common fire risk by placing glass items, whether empty or full, out of sunlight year-round.
Where Else This Can Happen Inside Your Home
Safety and environmental expert, Brian Dunagan, is Chief Investigator for fire, electrical, and explosion cases at IFO Group.
He adds that in investigations of these sorts of infernos, they usually come about ‘because sunlight passed through curved glass, acted as a lens, and the energy focused on combustible materials like paper, cardboard, fabrics or dry wood.’
Brian warns that it’s not just glass on windowsills that can cause a spark. He explains, ‘Countertops, shelves, sunrooms and patios, garages, and vehicle interiors can cause similar incidents when direct sunlight hits a transparent container.
‘The thickness of the glass alone is usually of minor importance compared to the shape of the container, clarity and contents. Ignition is not based on outdoor temperature. The intensity of the direct sunlight, angle of the sun, exposure duration and type of material being heated are all critical.’
Keeping these items out of the direct path of sunlight anywhere in your home, and having a fire extinguisher available from Amazon in the house, is vital for your household's safety.
How to Safely Store Reflective Objects Instead
‘Mirrors, crystals, glass ornaments, bottles and similar reflective items should be kept away from direct sunlight,’ former firefighter John adds, ‘and ideally stored in shaded areas, drawers or against walls where sunlight cannot hit them directly.’
If you don’t have storage space in cabinets, consider a chic fluted wall-mounted recycling bin from IKEA or hanging storage baskets from Williams Sonoma, which you can place on a wall or behind a door in a permanently shady spot.
I now have a spacious and sleek recycling bin from Caraway for used jars and bottles, and have recently expanded my kitchen storage with an IKEA Kallax Unit so no glass has to be left out in our sunny, south-facing kitchen.
What to Shop
I have added a KALLAX unit to my kitchen as it doesn't have enough cabinets and it's proven to be essential in keeping the space organized. Sunlight doesn't reach it so I have glass jars on top of it, and in a few of the drawers to keep my cabinets tidy.
I've found this double-layered recycling bin instrumental in tidying up the previously messy space we used to keep cardboard and glass before they went outside to our large recycling bin. It's easy to clean and accessible from the top and side.
Keep bread stored alongside your jars of breakfast jams. There is plenty of space in this 12.2'' H X 11.8'' W X 11.8'' D bamboo food storage bin, suitable for the corner of a kitchen worktop.
Hang these useful rattan baskets on a shady wall or door to provide instant expanded storage for your bottles, food and more.
This set of three compact extinguishers can be used on kitchen grease, wood, gasoline, and lithium-ion battery fires. Wall mount to avoid having to search the house for it in an emergency.
You can alternatively replace your glass jars with stainless steel cannisters. While these have a small glass viewing windows, this does not pose a risk the way curved fully glass vessels do.
Does it only happen during very hot weather?
John stresses that the risk of fire from glass and reflective objects in the home lasts all year. He says, ‘It isn't limited to heatwaves or summer months. Bright winter sunlight through windows can still create enough concentrated heat to ignite combustible materials.
What to do if a fire starts?
‘The priority should always be getting everyone out safely and calling for help immediately,’ John says. ‘If possible, close internal doors behind you to help slow the spread of smoke and flames, but never put yourself at risk trying to tackle a growing fire.’
Keeping a suitable fire extinguisher at home is a must-have for household safety.
Meet the Experts
Next, reduce the fire risk around your home by never putting particular items items on your porch.
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