Waking up to steamed-up windows every morning can be frustrating. You wipe them down, but they’re back again the next day. And while it might seem like a minor thing, constant condensation on your double glazed windows can turn into a bigger problem. It can lead to mould, rot, musty smells, or even damage to the frames. It makes your home feel damp, and that never feels nice, does it?
So if you’re tired of the fog and want to sort it out properly, you’re in the right place. This guide is for you. It breaks everything down simply—why it happens, what it means, and how to stop it. No overcomplicated advice. Just clear steps and fixes that actually help.
Why does condensation form on double glazed windows?
Let’s start here—because once you understand what causes it, it’s much easier to get under control.
Condensation happens when warm, moist air meets a cold surface. So when you’ve got the heating on and you’re cooking, showering, or just breathing indoors, the air builds up moisture. When that hits the cold surface of the window, it turns into droplets.
Even with double glazing, the inside pane can still get cold enough to cause that reaction—especially in winter or when ventilation’s poor.
Most of the time, this kind of condensation forms on the inside of the window. That’s normal in homes that are sealed up tight but still dealing with everyday moisture—things like drying clothes indoors, or not opening windows during showers or cooking.
But if you’re seeing condensation between the panes, that’s different. That usually means the sealed unit has failed. Moisture’s got inside the gap, and that’s not something you can just wipe off. It needs replacing.
Is condensation on double glazing something to worry about?
It depends where it’s forming. Condensation on the inside of the glass is common and fixable. But if it’s left to sit day after day, that moisture can cause:
- Mould on walls and sills
- Damage to wooden frames or plaster
- A cold, clammy feeling in the room
- Poor air quality and breathing problems for some people
So yes, it’s worth fixing. Not just because it looks bad or feels damp—but because it protects your home and makes it more comfortable.
How do you stop condensation on the inside of your double glazed windows?
Right—this is the part that really matters. Let’s go over what actually works. You don’t need fancy tech or major renovations to reduce condensation. You just need to manage the moisture in the air and improve airflow.
Here are the most effective things you can do:
Improve ventilation
This is the biggest and most helpful change you can make. If moisture can escape, it won’t build up.
- Open windows for 10–15 minutes in the morning to let stale air out.
- Use extractor fans in the kitchen and bathroom whenever you’re cooking or showering.
- Keep trickle vents open (those small slots at the top of some window frames).
Even a small window left slightly open can make a big difference. And if your windows don’t have vents, you can fit them pretty easily.
Control indoor humidity
Condensation is a symptom of high humidity. So reducing that level inside your home helps more than anything else.
- Use a dehumidifier in rooms that get damp often, like bedrooms or living areas.
- Avoid drying clothes on radiators or over doors if possible.
- Keep pan lids on when cooking and run the extractor fan or open the window.
You can buy a cheap humidity meter online to keep track of moisture levels. Aim for around 40% to 60% relative humidity indoors.
Keep a consistent room temperature
If your room’s temperature goes up and down a lot, it makes condensation worse. Cold air holds less moisture, so when a warm room suddenly cools down overnight, the water in the air condenses fast.
Try to keep your heating steady, especially in colder months. If you’re using timers, avoid letting the house drop too cold before warming back up again. Even keeping the thermostat at a lower but consistent level works better than turning it on and off.
Move furniture away from windows and external walls
When large furniture sits flush against cold walls or near windows, air can’t circulate. That space gets colder, and moisture settles. By pulling sofas, wardrobes or beds away slightly—just a few centimetres—you allow airflow to dry the air more evenly.
Wipe it down regularly (but don’t rely on this alone)
If you’ve already got condensation every day, start by wiping it off with a dry cloth or a window vacuum each morning. This won’t stop it coming back, but it stops it soaking into your sills and making things worse while you work on a longer-term fix.
Can double glazing be the problem itself?
Sometimes yes. If you’ve tried everything else and you’re still dealing with constant condensation on the inside, your windows might not be insulating as well as they should.
Older or lower-quality double glazing can let more cold through the inner pane, especially if the seal is worn. That cools the surface of the glass and encourages moisture to settle.
In some cases, replacing the window or the sealed unit can help. Look for condensation forming between the panes—that’s the giveaway that your double glazing unit has failed. When that happens, the insulating gas between the panes escapes, and the glass can no longer keep your indoor air and outdoor air separate.
Can you stop condensation between double glazing panes?
Not really—not without replacing the unit. If you’re seeing mist or droplets between the two layers of glass, the seal is broken and moisture has got inside.
You might find people online suggesting DIY fixes, like drilling holes to let air in or using drying agents. But these don’t fix the actual problem, and they can make it worse. The only real solution is to replace the double-glazed unit. The frame itself doesn’t need to come out—just the glass part.
It’s usually cheaper and faster than replacing the whole window, and it restores the insulating performance straight away.
Are there any long-term solutions worth investing in?
Yes—if you’re looking for permanent changes that stop condensation for good, here are some options worth thinking about:
- Install passive air vents or heat recovery units: These help circulate air without losing too much heat.
- Upgrade extractor fans: Some modern fans have humidity sensors that turn on automatically.
- Replace older windows with high-quality units: Especially if you’ve already got failed seals or outdated glazing.
- Improve insulation: If your home’s poorly insulated, surfaces inside can stay cold even with good heating. Adding insulation helps walls and windows stay warmer, which reduces condensation.
None of these need doing overnight, but they’re worth keeping in mind if you’re doing home improvements anyway.
What can you do right now to get started?
If you’re staring at fogged-up windows every morning, don’t wait for it to become a bigger problem. Start with the basics:
- Open your windows for a few minutes each day
- Use the fans you already have
- Move furniture slightly away from windows
- Wipe the glass down to stop water sitting for too long
- Think about getting a dehumidifier, especially for colder months
These small steps really add up. You’ll notice less condensation within days if you keep at it.
Why it’s worth sorting condensation sooner rather than later
At first, it might just seem like a bit of fog. But if you ignore it, condensation can lead to black mould, musty smells, and even damage to plaster and paintwork. It affects your health and your home.
Stopping it now means a warmer, drier space that feels better to live in. It protects your windows, lowers your heating costs, and gives you control over the air you breathe every day.
So even though it seems like a small issue, it’s one that’s well worth fixing—and it’s easier to deal with than you might think.
You don’t need to rip everything out or spend loads of money. You just need a bit of airflow, a bit of awareness, and a few consistent habits. Once you’ve got those in place, the fog clears—and stays away.
Glaziers Newport Pagnell – Glaziers Leighton Buzzard – Glaziers St Albans
