7 items experts warn you should never put on a windowsill – or risk a safety hazard

It seems a shame to leave a windowsill bare and not utilise its potential as an extra space for decorative and storage purposes. And while that might be true in some cases, there are certain things you should never put on a windowsill as it could pose a safety hazard or cause damage to those very objects.

Placing decorative objects on your windowsill can sometimes be a beautiful way to dress a window, or use that extra space in a practical way for storage. But making it full and cluttered is never a good idea as it could interfere with the functionality of your window or obstruct a potential escape route in case of emergency.

But besides that, there are 7 types of items that most definitely shouldn’t be found on a windowsill according to experts. Let's find out what they are...

7 things not to put on a windowsill

If you have some of these things on your windowsill at this very moment, there’s no judgement here as we’re guilty of having done the same thing. Decorating a windowsill seems like a great way how to dress a window.

That’s why we love to keep everything from a vase of flowers to Aldi’s windowsill greenhouse on our windowsills. But it turns out that some things are less suitable to be placed there than others.

1. Don’t put books on a windowsill

Books don’t exactly pose a hazard. But by keeping them on a windowsill you are risking they will get faded by the sun coming through the window over time.

‘Books need to be avoided as direct sunlight and heat can damage and fade the ink or discolour the pages of books over time,’ says Allan Reid from Art Windows & Doors.

And this also applies if you keep books on a bookshelf right next to a window, actually.

2. Don’t keep cleaning products on a windowsill

Cleaning products contain chemicals. And when you introduce heat into the chemical equation, it could end badly even for the best of cleaning products.

‘Storing cleaning products on a windowsill may seem convenient, but it can lead to accidents and chemical degradation due to temperature fluctuations,’ says Danny Stalman from leading window company, Plan-It Windows. ‘It's better to keep these products in a stable, cool, and dry environment to maintain their effectiveness.’ 

‘Sunlight exposure can increase the volatility of these products, potentially causing containers to break down. This not only poses a spill hazard but also a safety risk, as many cleaning agents are corrosive or reactive. Additionally, evaporated chemicals can contaminate indoor air, contributing to a toxic environment.’

3. Don’t place candles on a windowsill

Keeping your best scented candles on the windowsill can pose both a fire hazard and a risk of damage to the candle itself.

‘Candles can transform a room with their scent and ambience, but they should never be left on a windowsill,' Danny says. 'When wax softens, it can lead to functional problems like improper burning, as well as changes in shape and texture that affect its appearance. Also, when exposed to high temperatures, the scents mixed into the wax might alter or fade, reducing the enjoyable aromas they are meant to release.’

'Candles, matches or lighters pose a fire hazard on a windowsill, especially near flammable curtains,' adds Allan.

4. Don’t put mirrors on a windowsill

Last year, an Instagrammer placed a mirror on her windowsill and ended up with a burned window. And this is not an isolated incident - putting a mirror on the windowsill could actually set your house on fire.

‘We often see homeowners placing decorative items on their windowsills without considering the potential for fire. Objects like mirrors or any reflective items can act like a magnifying glass under the sun's rays, focusing heat on a single point and igniting nearby materials. We advise removing these from windowsills to prevent the risk of potential fire outbreaks,’ Danny warns.

5. Don’t display fragile decor on a windowsill

If you have any sentimental or valuable items that could also easily be broken, then don’t display them on a windowsill and opt for something like a bookshelf instead.

‘While placing sentimental or decorative items on a windowsill might seem appealing, it poses several risks,' warns Danny. 'Sudden winds or accidental nudges can send these valuable items crashing to the floor. Furthermore, they can obstruct the operation of the window, preventing essential ventilation.'

6. Don’t set perfumes and beauty products on a windowsill

Similarly to cleaning products becoming spoiled from the sun heat coming through the window, the same can happen to your beauty products and perfumes if you set them on a windowsill.

‘Avoid beauty products or medications as they can break down or separate when exposed to heat and sunlight,' cautions Allan. 'Perfumes, for example, can lose their scent or even turn cloudy.'

7. Don’t place aerosols on a windowsill

And aerosols are even worse to be put on a windowsill than other beauty products due to their packaging which could actually explode in certain unfortunate conditions.

‘Aerosols and flammable items on a windowsill are a significant hazard, especially during warmer seasons,' explains Danny. 'The sunlight can heat these items to dangerous levels, leading to potential explosions.'

‘Direct sunlight can speed up the breakdown of chemicals in these products, which might not only reduce their effectiveness but also make them unstable. Over time, weakened containers might burst, causing hazards and possibly leading to health risks from inhaling toxic substances,’ he concludes.

So perhaps it’s time to clear those windowsills to avoid any unfortunate situations. It’s better to be safe than sorry.