There are two completely different reasons your windows might be steaming up, and only one of them is actually about the windows themselves. Condensation on the inside surface of the glass is a humidity problem, fixable with ventilation and a few daily habits. Condensation trapped between the two panes of a double-glazed window is a genuine fault that no amount of wiping or airing will solve. Working out which one you’ve got is the first step, and it’s the one thing most guides skip over.
If the condensation is on the inside surface of the glass, it’s a humidity problem rather than a window problem. Moisture from cooking, showering, drying clothes and breathing settles on the coldest surface in the room, and in winter that’s the window. Ventilation and a few daily habits fix it.
If the misting is trapped between the two panes of a double-glazed window, the seal has failed, and no amount of wiping or airing will solve it. That needs a window professional.
Check which side of the glass the condensation is on before you do anything else.
The two types of window condensation, and why the difference matters
Condensation on the inside surface of your window, the side facing into the room, is by far the more common of the two, and it’s entirely fixable with ventilation and a few daily habits. This is what most people mean when they say their windows “steam up.”
Condensation between the two panes of a double-glazed window is a different and more serious sign. If you can see misting or water sitting inside the sealed unit itself, between the glass rather than on either surface, this means the seal has failed and the unit is no longer holding its insulating gas properly. No amount of ventilation or wiping fixes this. It needs a window professional to repair or replace the sealed unit.
Which one have you got?
- What you seeMisting on the room side of the glassLikely causeToo much moisture in the airStart hereVentilation and the daily habits below
- What you seeKitchen windows steam up while you cookLikely causeCooking moisture with nowhere to goStart hereRun the extractor with the kitchen door closed
- What you seeBathroom window soaked after a showerLikely causeShower moisture spreading through the houseStart hereRun the extractor with the bathroom door closed
- What you seeMisting or water between the two panesLikely causeThe sealed unit has failedStart hereCall a window professional, not a cloth
- What you seeWet windows every morning, plus a musty smell or early mouldLikely causeA wider humidity problem in the roomStart hereSee when it's more than just the windows, below
Why surface condensation happens
Warm, moist air reaches its dew point the moment it touches a cold surface, and a window pane is almost always the coldest surface in a room, especially overnight or first thing in the morning. An average UK household produces around 21 pints of water vapour a day, roughly 12 litres, just from breathing, cooking, showering, and drying clothes. In winter, with windows shut and the heating on, that moisture has nowhere to go except onto the coldest surface available.
For the full explanation of why this happens more in winter specifically, and what it means for the rest of your home beyond just the windows, see our guide to why your house might be so damp in winter.
What actually helps
Ventilate the room the moisture is coming from
Use the extractor fan in the kitchen while cooking and the bathroom while showering, and keep the door to that room closed while the fan runs, so the moist air is pulled outside rather than spreading into the rest of the house and settling on cooler windows elsewhere.
Open a window briefly, even in winter
A few minutes of genuine airflow lets the moist air escape before it has a chance to condense, and it’s more effective than people expect for how little heat it actually loses.
Wipe condensation off first thing each morning
Don’t leave it to sit on the glass and frame all day. Left long enough, this moisture works into the frame and seal and becomes the starting point for mould. A dedicated window vacuum does this job considerably faster and more thoroughly than a cloth.
When it's more than just the windows
If the misting is between the two panes of a double-glazed window rather than on the glass you can wipe, the seal has failed. No amount of ventilation or wiping fixes this. It needs a window professional to repair or replace the sealed unit.
If wiping the windows each morning has become a genuine daily routine that never seems to end, and you’re also noticing a musty smell or the early signs of mould elsewhere in the room, the windows are likely a symptom of a wider humidity problem rather than the problem itself. Our guides to best dehumidifiers for small UK homes and whether dehumidifiers actually help with mould cover the broader fix once the problem has moved beyond the glass itself.
The quick checklist
- Check which side the condensation is on: inside surface (fixable) or between the panes (needs a professional)
- Use extractor fans in the kitchen and bathroom, with the door closed while they run
- Open a window briefly each day to let moist air escape
- Wipe condensation off the glass every morning before it settles into the frame
- Try the washing-up liquid trick on a genuinely stubborn window
- If it's between the panes, call a window professional, not a cloth
Steamed up windows: your questions answered
Why do my windows steam up more in winter than summer?
In winter, homes are sealed up with windows shut and heating running, so the moisture produced by everyday activities like cooking, showering, and breathing has nowhere to escape. Windows are also usually the coldest surface in a room during winter, which means warm, moist air condenses onto them the moment it touches the glass. In summer, open windows and warmer overall temperatures let that same moisture escape before it has a chance to settle.
Is condensation on the inside of my windows a sign of a problem with the windows?
No, usually not. Condensation on the inside surface of the glass is almost always a humidity and ventilation issue in the room, not a fault with the window itself. Condensation trapped between the two panes of a double-glazed window is different, and does indicate a genuine fault, a failed seal in the sealed unit, which needs professional repair or replacement rather than any amount of ventilation or cleaning.
What does it mean if condensation is between the two panes of glass?
This means the sealed unit inside your double glazing has failed, allowing air to enter the gap between the panes. It cannot be fixed by ventilation, cleaning, or anything done from inside the room, since the problem is inside the sealed unit itself. It typically requires a window professional to repair or replace the affected pane, and it usually also means the window is losing more heat than it should due to the reduced insulating performance.
Does washing-up liquid actually stop windows steaming up?
It can genuinely help as a temporary measure. Rubbing a small amount of washing-up liquid onto the glass with a damp cloth, then buffing it dry, leaves a very thin film that makes it harder for water droplets to form on the surface, working in a similar way to an anti-fog treatment. It is not a permanent fix and needs reapplying periodically, but it can noticeably reduce condensation on a specific problem window between proper ventilation habits.
How often should I wipe condensation off my windows?
Ideally every morning during the colder months, particularly in bedrooms and bathrooms where moisture builds up overnight or after showering. Left to sit, condensation on the glass and frame is one of the most common starting points for mould, particularly around the seal. Wiping it away each morning, whether with a cloth or a dedicated window vacuum, takes only a couple of minutes and meaningfully reduces the risk.
Will opening a window in winter make my house colder overall?
A few minutes of ventilation loses far less heat than most people expect, and it’s genuinely worth it to let moist air escape before it settles as condensation. The heat lost during a brief airing is quickly recovered once the window is closed and the heating continues, whereas the moisture that would otherwise condense on the glass can contribute to a longer-term damp or mould problem that costs more to fix than a few minutes of lost warmth.
