Double glazed windows are a great feature in any home. They keep the heat in, reduce noise from outside, and make your house more energy efficient. But like any part of your property, they need looking after. Dirt, dust, and condensation can build up, leaving your windows cloudy or streaked. While cleaning the outside panes is straightforward enough, the question that confuses most homeowners is this: how do you clean inside double glazed windows?
The reason this is a common question is because the panes in double glazing are sealed together. That sealed gap is what traps the air or gas that gives you insulation. It also means you can’t just take the glass apart to wipe the inside when you notice dirt or fogging between the panes. Sometimes what looks like a simple cleaning job is actually a sign of a seal failure, which can only be properly fixed by repair or replacement.
That said, there are parts of your double glazed windows you can clean — the interior surfaces you can reach, the frames, and the seals around the edges. There are also ways to deal with issues like condensation or haze, at least temporarily, until you decide on a longer-term fix.
In this guide, we’ll go through everything step by step. You’ll learn how to clean the accessible areas of your double glazed windows properly, how to keep frames and seals in good shape, what to do if condensation appears between the panes, and how to handle other common problems like scratches or hazy patches. By the end, you’ll know exactly what you can do yourself, and when it makes more sense to call in the professionals.
How to Clean Inside Double Glazed Windows
When people talk about cleaning “inside” double glazed windows, it’s important to be clear about what that means. If you’re talking about the side of the glass that faces into your room, that’s no different from cleaning a normal window — you just need the right cloth and a decent glass cleaner. But if you’re talking about dirt or condensation trapped in between the two panes of glass, that’s something you can’t simply wipe away.
To avoid confusion, let’s start with the parts you can clean safely.
Gather Your Supplies
Before you start, get everything ready so you’re not running around mid-job. You’ll need:
- A soft microfibre cloth (these leave fewer streaks).
- A spray bottle with either distilled water or a mild glass cleaner.
- A vacuum cleaner with a brush attachment, useful for dust around the frames.
- A small, soft-bristled brush for awkward corners.
- Optional: a ladder or step stool if you’re cleaning tall windows.
It’s best to avoid strong chemicals like ammonia or bleach because these can damage the seals and leave the glass looking worse. Distilled water is great because it doesn’t leave water marks behind when it dries.
Clean the Outside First
It might seem odd to start outside when you’re focused on the inside, but there’s a good reason. If your outside glass is dirty, it’s harder to see clearly what’s happening on the inside. Give the external panes a good clean first so that when you tackle the interior, you’re not left second-guessing whether the smudges are inside or outside.
Accessing the Inside
For most sealed units, you can’t and shouldn’t try to take the panes apart. The seal is what keeps the insulation effective. If that seal is broken, the double glazing won’t perform as it should, and it’s not something that can be resealed at home. That’s why if you notice actual dirt or moisture inside the sealed cavity, cleaning alone won’t fix it. We’ll talk more about condensation between the panes later.
What you can do is clean the room-facing glass carefully. Spray a light mist of distilled water or cleaner, wipe with your microfibre cloth, and buff dry with a second cloth to remove streaks. Work in small sections so the liquid doesn’t dry before you wipe it.
Don’t Forget the Edges
Around the edges of the panes, dirt and grime often build up. Use your small brush to loosen anything stuck in the corners, then vacuum gently with the brush attachment. Wipe down afterwards with a slightly damp cloth.
Dry and Inspect
Once you’ve cleaned everything, dry the surfaces with a clean, dry cloth. Check your work in daylight, as streaks and marks are much easier to spot in natural light.
A Word of Caution
If you’ve noticed fogging, condensation, or actual dirt between the two panes of glass, cleaning the surface won’t solve it. That’s a sign of a failed seal, which means the insulating barrier has been compromised. In those cases, the only long-term solution is professional repair or window replacement.
So while you can clean the accessible surfaces of your double glazed windows just like any other, the sealed gap in the middle is off-limits for DIY cleaning.
Cleaning Window Frames and Seals
The glass itself gets most of the attention, but the frames and seals are just as important. Clean frames look better, and clean seals help extend the life of your windows.
uPVC Frames
Most modern double glazing comes with uPVC frames. These are fairly low maintenance, but they do pick up dirt and grime over time. A bucket of warm soapy water and a soft cloth is usually all you need. Avoid anything abrasive because it can scratch the surface and make the frames harder to keep clean in the future.
Wooden Frames
If you’ve got wooden frames, you’ll need to be more careful. Excess water can cause swelling or rot, so stick to a damp cloth rather than soaking the wood. Dry thoroughly afterwards. For stubborn spots, a gentle wood cleaner is fine, but don’t use anything harsh that could strip protective coatings.
Aluminium Frames
Aluminium frames are strong and weather-resistant but can sometimes show signs of corrosion. A simple wipe down with warm water and a soft cloth usually does the job. If you notice any powdery residue, it could be oxidation, which may need specialist care.
Rubber Seals
The seals around the glass are designed to keep moisture out and insulation in. They also collect dirt, which can weaken them over time. Clean these with mild soapy water and a soft sponge. Don’t scrub too hard, as rough treatment can pull the seal away from the glass.
By keeping frames and seals clean, you’ll not only improve the look of your windows but also help prevent problems like condensation and leaks.
Dealing with Condensation Between Panes
One of the most frustrating problems homeowners face with double glazing is condensation trapped inside the unit. You might wake up one morning to find your windows foggy from the inside, with droplets of water forming between the panes. Unfortunately, this is a telltale sign that the seal has failed.
Why Condensation Happens
Double glazing works by sealing two panes of glass with a gap in between, often filled with air or an insulating gas. If the seal is damaged, moisture can creep in. Once it’s there, it lingers because the air space is sealed off, making it difficult to clear.
Temporary Fixes
There are a few short-term tricks you can try to reduce condensation:
- Place a dehumidifier in the room to lower moisture levels.
- Use silica packs or moisture absorbers near the window.
- A gentle warm air blast from a hairdryer can sometimes evaporate visible condensation.
These methods can help in the short run, but they won’t repair the failed seal.
Long-Term Solutions
The only lasting fix is either professional resealing or replacing the sealed unit. Some companies can drill tiny holes to remove moisture and reseal the unit, but this doesn’t always restore full insulation. Replacement is often the most reliable option.
Prevention
You can’t always prevent seal failure, but you can help delay it. Keep rooms ventilated, avoid letting moisture sit on the frames, and maintain seals with regular cleaning.
Fixing Haze, Scratches, or Other Issues
Aside from condensation, there are a few other common problems with double glazing.
Haze
Sometimes the glass looks cloudy or hazy, even when it’s clean. This can be residue left behind by condensation or simply dirt you can’t reach between the panes. Unfortunately, if the haze is inside the sealed cavity, the only real fix is repair or replacement. On the outer surfaces, a specialist glass cleaner can usually help.
Scratches
Light scratches can often be polished out using a specialist product like cerium oxide paste. Apply gently with a soft cloth, working in small circles. Be cautious, though: deeper scratches are harder to remove and can make things worse if you rub too hard. If the scratch is significant, professional repair or replacement may be needed.
Other Issues
Mould can sometimes appear around seals if moisture is present. A gentle cleaner and a soft cloth can usually remove it, but persistent mould may indicate deeper problems. Staining from hard water can also be an issue; vinegar-based cleaners can sometimes help, but avoid overuse as it may harm seals.
When problems go beyond what a cloth and cleaner can fix, it’s best to consult a professional. Attempting DIY fixes on serious issues can make things worse or reduce the efficiency of your windows.
Our Final Say!
Cleaning the inside of double glazed windows can seem like a challenge, but the key is knowing what you can and can’t do yourself. The inner surfaces that face into your home are easy enough to clean with the right tools and a gentle approach. Frames and seals benefit from regular attention too, helping to keep your windows looking good and performing well.
When it comes to condensation, haze, or dirt trapped between the panes, that’s not something you can fix with a cloth. Those problems are signs of seal failure, which usually means professional repair or replacement. It may feel frustrating, but it’s better to tackle the root cause than waste time on temporary fixes that don’t last.
The good news is that you don’t have to live with cloudy or unattractive windows. With proper cleaning and maintenance — and professional support when you need it — you can keep your double glazing clear, efficient, and in top condition for years to come.
Call Abacus Window Cleaning Today!
At Abacus Window Cleaning, we know how important clear, well-maintained windows are for your home. Our team has the knowledge and the tools to clean your windows safely, without damaging delicate seals or leaving streaks behind. We also understand the frustrations of condensation, haze, and other common glazing problems, and we’re here to help you find the right solution.
By choosing Abacus, you can avoid the risks of DIY cleaning and enjoy the peace of mind that comes from a professional finish. We’ll save you time, effort, and money in the long run by making sure your windows are cleaned properly the first time.
If you’d like to find out more or book a window clean, give us a call today on 01252 834238. We’ll be happy to answer your questions, provide advice, or arrange a service at a time that suits you. Let Abacus Window Cleaning take care of your windows so you can get back to enjoying the view.
