If you wake up most winter mornings wiping water off the bedroom window with a towel, you are not alone. That foggy glass is more than a minor annoyance. Over time, the constant damp can stain paint, swell wood, and create a perfect little playground for mold.
So when a woman in the United Kingdom said she had cut her nighttime condensation simply by putting a tiny bowl of table salt on the windowsill, for about 65 pence (under one dollar), the story spread fast.
A tiny kitchen staple on the windowsill
Her problem will sound familiar. Every morning, the inside of the bedroom window was covered in mist and beads of water. Cracking the window open helped a bit, but on cold nights that is not always comfortable or affordable.
Curious about an old-fashioned trick, she picked up cheap table salt from Sainsbury’s, filled a small bowl, and parked it on the sill before bed.
By morning, there was far less moisture on the glass and the salt was damp and clumped together, a sign it had soaked up water from the air. She now leaves a bowl out each night and refreshes the salt every few days.
Her experience is not unique. Lifestyle outlets including Homes & Gardens, UK radio brand Heart, and Canadian outlet The Weather Network have all highlighted the bowl of salt trick as a quick, low-cost way to dial down minor condensation for people who cannot run a dehumidifier all day.
Why those droplets keep coming back
Condensation on windows happens when warm, humid indoor air hits a cold surface and cannot hold all that moisture anymore. The excess water falls out of the air and settles on the glass as a misty film or droplets. Everyday life feeds that humidity. Cooking, showering, drying laundry inside, even just having people breathing in a small room all add water to the air.
Experts who study home energy and window performance note that the problem usually peaks in winter. The outside temperature cools the windowpane while we try to keep living rooms and bedrooms warm and cozy.
That temperature gap makes windows one of the first places indoor moisture shows up. Even modern double glazing will fog if the room is humid and poorly ventilated.
When condensation turns into a health problem
Left alone, little pools of water on sills and corners can slowly soak into plaster and caulk. That damp surface is where mold often begins. Public health agencies, including the World Health Organization, have linked living in damp, moldy homes with higher rates of coughing, wheezing, allergies, and asthma, especially in children.
The American Lung Association warns that mold spores and indoor dampness can trigger asthma symptoms and other breathing problems even in adults who do not normally think of themselves as sensitive. That is why a small trick that nudges humidity down near a problem window can matter more than just saving the paintwork.
What the salt in the bowl is actually doing
So how could a pantry staple help with a problem that serious? At a chemical level, ordinary sodium chloride is mildly hygroscopic, which means it can absorb some moisture from the surrounding air. It is not nearly as powerful as specialist products that use calcium chloride or silica gel, but it does act like a tiny, passive dehumidifier once you pour it into an open dish.
In informal tests reported by Homes & Gardens and other home advice sites, bowls of salt placed on or near windowsills made glass noticeably less cloudy in small apartments and bedrooms that did not have major damp issues.
An expert quoted by those outlets explained that salt can bind to water on its surface and pull a little moisture out of the air closest to the window. Once the crystals are saturated and clumpy, though, they stop working and need to be replaced.
In practical terms, the bowl creates a slightly drier microclimate right where warm room air meets the cold glass. That can reduce the amount of water that ends up condensing there overnight, even if it does not change the humidity in the rest of the room very much.
How to try the salt trick at home
If you want to experiment, the method is very simple. Use a small ceramic or glass bowl that will not tip easily. Fill it with plain table salt rather than coarse rock salt, since the finer grains offer more surface area. Set the bowl on the sill or just in front of the coldest window in the room, ideally in the evening so it has time to work before temperatures drop.
Check the salt every couple of days. If it feels wet, forms a crust, or starts to puddle, throw it out and refill the bowl. For rooms with several problem windows, you may need more than one dish.
It is also smart to keep salt away from pets and young children and avoid resting a salty, damp bowl directly on bare metal, since salt water can corrode some finishes over time.
A helpful hack, not a full solution
Chemists point out that sodium chloride only absorbs a limited amount of water and is a weaker drying agent than products based on calcium chloride. So a bowl of salt will not fix serious damp issues, leaks, or structural problems.
If your windows are streaming every morning, or if you already see mold on walls and ceilings, you still need better ventilation and possibly a mechanical dehumidifier, along with repairs if moisture is coming from outside.
Home experts recommend simple steps that work alongside the salt. Open windows briefly each day to create a cross breeze, especially after showers or cooking. Use bathroom and kitchen exhaust fans, avoid drying clothes indoors when you can, and keep furniture a little away from cold exterior walls so air can circulate.
Keeping indoor temperatures steady rather than cycling between very cold and very hot also reduces condensation.
At the end of the day, a small bowl of cheap salt will not replace good windows, decent heating, and fresh air, but it can cut down the amount you have to wipe off the glass every morning and may slow the march of damp into corners and frames.
