How to Clean Double Glazed Windows: Streak-Free Results

Short answer: you can clean the room-facing and outside surfaces of double glazed windows, the frames and the seals yourself, using microfibre, a squeegee and a mild solution. You cannot clean between the two panes. If you can see mist, droplets or dirt in that gap, the sealed unit has failed, and the fix is a replacement unit from a glazing company, not a better cloth.

The rest of this guide follows that split: how to get streak-free glass, how to look after uPVC, wooden and aluminium frames and the rubber seals, how to use tilting easy-clean windows safely, and what to do about misting in the cavity. A plain-English kit list and a short set of questions sit at the end.

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What you can clean, and what you cannot

Before grabbing your cleaning supplies, it’s helpful to understand what you’re working with. Double glazed windows consist of two panes of glass separated by a sealed gap, usually filled with air or an insulating gas like argon. This sealed space is what makes these windows so effective at keeping your home warm and reducing outside noise.

The seal between the panes is critical. It’s designed to be completely airtight, preventing moisture, dust, and dirt from getting into that gap. When your windows are functioning properly, this seal stays intact for years, and you’ll only ever need to clean the surfaces you can reach, the interior glass facing your room and the exterior glass facing outside.

What “Inside” Really Means

Here’s where the confusion happens. When you search for “how to clean inside double glazed windows,” you might be asking about:

1. The interior-facing glass, the surface you can touch from inside your room (this is cleanable)
2. The exterior-facing glass, the surface facing outside (also cleanable)
3. The space between the two panes, the sealed cavity (NOT accessible without breaking the seal)

If you can simply wipe away what you’re seeing, it’s on an accessible surface. If there’s fogging, condensation, or dirt that won’t budge no matter which side you clean from, that’s between the panes, and that’s a seal failure problem, not a cleaning problem.

Signs Your Seal Has Failed

You’ll know you have a seal failure if you notice:

• Condensation or water droplets between the glass that won’t wipe away
• Foggy or cloudy appearance that persists regardless of cleaning
• Visible dirt or dust floating inside the sealed space
• A milky or hazy film between the panes

Warning: Never attempt to separate the two panes of glass yourself to clean between them. This can destroy the window’s insulating properties and void any warranty. Seal failures require professional assessment and repair.

If you’re seeing any of these signs, skip ahead to our section on condensation between panes. For normal cleaning of accessible surfaces, let’s get started with the proper technique.

If you are unsure which surface the problem is on, wipe the glass on one side and then the other. A mark that moves is on the surface. A mark that stays put whichever side you clean is inside the unit.

Streak-free glass, step by step

The key to sparkling double glazed windows is using the right materials and technique. Most streaks happen because of three common mistakes: using too much cleaner, working in direct sunlight, or using dirty cloths. Avoid these pitfalls, and you’ll get professional-looking results.

What You’ll Need

Essential Tools:

• Microfibre cloths, at least two (one for cleaning, one for buffing). These are superior to paper towels as they don’t leave lint behind
• Squeegee with rubber blade, the secret weapon for streak-free windows
• Spray bottle, for your cleaning solution
• Vacuum cleaner with brush attachment, for removing dust before cleaning
• Soft-bristled brush, an old toothbrush works brilliantly for corners

Cleaning Solutions (Choose One):

• Distilled water, surprisingly effective on its own and leaves no residue
• White vinegar solution, 1 part white vinegar to 2 parts water (eco-friendly and excellent for cutting through grime)
• Mild washing-up liquid solution, just a few drops in warm water
• Commercial glass cleaner, choose a non-abrasive formula

What to AVOID:

• Bleach (especially on uPVC frames, it causes brown discolouration)
• Ammonia-based cleaners
• Cream cleaners or scouring powders
• Wire wool or abrasive sponges
• Newspaper (despite old wives’ tales, it can leave ink residue on modern frames)

Tip: Distilled water costs very little and has no dissolved minerals to dry into spots or streaks, so it is worth buying if your tap water is hard. It also works on its own for a light clean.

Step-by-Step Cleaning Process

Step 1: Choose the Right Time

Timing makes a massive difference to your results. Clean your windows on a cloudy day or when they’re in shade. Direct sunlight causes your cleaning solution to evaporate too quickly, leaving streaks before you can wipe them away. Early morning or evening works well, or take advantage of overcast days.

Step 2: Remove Dust and Debris First

This step prevents scratches and makes the actual cleaning much easier:

1. Vacuum the frames and sills using a soft brush attachment. Pay special attention to corners where dust accumulates.
2. Brush away loose dirt from the glass surface with a dry microfibre cloth or soft brush.
3. Clean corners and edges thoroughly, this is where most grime hides.

Why bother? Because if you spray water onto a dusty window, you’ll create muddy streaks that are harder to remove than the original dust.

Step 3: Start with the Exterior Glass

Always clean the outside first. This gives you a clear view through the glass when you tackle the interior, making it easier to spot any remaining marks.

1. Spray your cleaning solution lightly across the glass (don’t drench it, less is more)
2. Wipe in sections using a damp microfibre cloth, working from top to bottom
3. Use your squeegee in an S-pattern or overlapping vertical strokes, wiping the blade clean after each pass
4. Buff any remaining moisture with a dry microfibre cloth

For ground-floor windows, this is straightforward. For first-floor windows or higher, consider using an extension pole with a squeegee attachment, or simply stick to cleaning what you can safely reach. There’s no shame in calling professional window cleaners for high or hard-to-reach windows, it’s much safer.

Step 4: Clean the Interior Glass

Now for the inside surface:

1. Spray your solution onto the glass (or onto your cloth to avoid overspray on windowsills)
2. Wipe in circular motions or from top to bottom, working in small sections
3. Use the squeegee technique, start at the top corner and pull down in straight, overlapping strokes
4. Wipe the squeegee blade with a clean cloth after each stroke
5. Buff with a dry microfibre cloth to eliminate any remaining streaks
6. Check your work in natural light from different angles

Tip: The squeegee S-pattern is worth learning: start at the top left, pull the squeegee diagonally down to the right, then reverse direction and overlap slightly. It reduces the number of times you lift the blade off the glass, which is when streaks start.

Step 5: Final Inspection

Stand back and look at your windows from different angles. Natural light will reveal any streaks or smudges you’ve missed. If you spot any, simply buff them away with a clean, dry microfibre cloth. Don’t re-wet the glass unless absolutely necessary.

Why Streaks Happen (And How to Prevent Them)

Even with the right technique, streaks can still appear. Here’s why:

Too Much Cleaning Solution Using excessive cleaner leaves residue that dries into streaks. A light mist is all you need, your cloth should be damp, not dripping.

Dirty Cloths Once a microfibre cloth is saturated with dirt, it just redistributes grime across your windows. Switch to a fresh cloth when the first one gets dirty, and always use a completely dry cloth for final buffing.

Hard Water If you’re using tap water in your cleaning solution, minerals can leave spots. Switch to distilled water for better results.

Rushing the Process Taking your time and working in small sections gives you better control. Trying to clean an entire large window in one go usually results in the solution drying before you can wipe it properly.

Wrong Temperature Both very hot and very cold temperatures can affect how your cleaning solution works. Room temperature or slightly warm water is ideal.

If you’re interested in more professional techniques, check out our guide on what window cleaners use to clean windows for additional insights.

For a wider look at the method, see our guide to cleaning windows without streaks.

Frames, seals and sills

Sparkling glass only looks its best when the frames are clean too. Different frame materials need different approaches, but the golden rule is the same: gentle cleaning with non-abrasive materials.

Cleaning uPVC Window Frames

uPVC (unplasticised polyvinyl chloride) is the most common frame material for modern double glazed windows in the UK. It’s popular because it’s low-maintenance and durable, but it does require regular cleaning to prevent discolouration.

The Basic Method:

1. Mix warm water with a few drops of washing-up liquid in a bowl or spray bottle
2. Dip a soft cloth or sponge in the solution and wring out excess water
3. Wipe down all frame surfaces, paying attention to corners and crevices
4. Rinse with clean water on a fresh cloth
5. Dry thoroughly with a clean, dry cloth

For Stubborn Dirt on uPVC:

If warm soapy water isn’t shifting the grime, try this vinegar method:

1. Mix 1 cup of white vinegar with 4 cups of hot water in a spray bottle
2. Spray the solution onto the uPVC frames
3. Leave for 10 minutes to allow the vinegar to break down the dirt
4. Wipe clean with a soft cloth
5. Rinse with clean water and dry

Alternatively, baby wipes are surprisingly effective for quick cleaning of uPVC frames. They’re gentle, pre-moistened with a mild solution, and convenient for regular maintenance.

Commercial uPVC Cleaners:

For heavily soiled frames, you can use a dedicated uPVC cleaner from your local hardware shop. Follow the manufacturer’s instructions carefully, and always test on an inconspicuous area first.

Warning: NEVER use bleach, white spirits, methylated spirits, or WD-40 on uPVC frames. Bleach can turn white uPVC frames brown or yellow, and solvents can damage the surface permanently. Cream cleaners should also be avoided as they contain abrasives that create tiny scratches, making frames look dull and harder to clean in future.

Cleaning Wooden Frames

Wooden frames require a gentler touch because excess moisture can cause swelling, warping, or rot.

1. Use a barely damp cloth with a tiny amount of mild wood cleaner or washing-up liquid
2. Wipe down the frames gently
3. Dry immediately and thoroughly with a clean cloth
4. Never soak wooden frames or leave them wet

For stubborn marks on wood, use a specialist wood cleaner designed for painted or varnished surfaces. Avoid anything too harsh that might strip the protective coating.

Cleaning Aluminium Frames

Aluminium frames are robust and weather-resistant, but they can sometimes develop a white powdery substance (oxidation).

1. Wipe down with warm, soapy water using a soft cloth
2. For oxidation, use a specialist aluminium cleaner or a very mild abrasive (though test first)
3. Rinse thoroughly and dry

Cleaning Rubber Seals

The rubber seals around your windows are crucial for keeping moisture out and warmth in. They’re also dust magnets, and dirty seals can degrade faster.

How to Clean Rubber Seals:

1. Use warm, soapy water and a soft cloth or sponge
2. For stubborn dirt in crevices, use a soft brush (like an old toothbrush) to gently dislodge debris
3. Wipe clean and dry thoroughly
4. Avoid harsh chemicals that can cause the rubber to perish, discolour, or peel

Tip: If you have coloured window frames, use a cloth that matches the frame colour when cleaning rubber seals. This prevents potential colour transfer from the cloth to the seals.

Inspect While You Clean:

As you clean your seals, check for:

• Cracks or splits in the rubber
• Sections pulling away from the frame
• Hardening or loss of flexibility
• Mould growth

If you notice significant damage, the seals may need professional replacement to maintain your windows’ energy efficiency.

Cleaning Window Sills

Don’t forget the sills, they accumulate dust, dead insects, and grime.

1. Vacuum or brush away loose debris first
2. Wipe with warm, soapy water using a non-abrasive cloth or sponge
3. For stubborn dirt, let the soapy water sit for 5 minutes before scrubbing gently
4. Rinse with clean water and dry

For more detailed guidance on cleaning the entire window area, including tracks and sills, see our comprehensive guide on how to clean window tracks.

Tilting easy-clean windows, and cleaning upstairs safely

Many modern double glazed windows have an “easy clean” mechanism that tilts the window inward, allowing you to clean the exterior glass from inside your home. This is particularly useful for upper-floor windows.

Understanding Easy Clean Windows

If your windows have this feature, you’ll find special tabs or buttons on the window mechanism, usually one at the top and one at the bottom of the hinge side.

How to Activate Easy Clean Mode

1. Open your window fully as you normally would
2. Locate the grooved metal tabs marked “easy clean” on the inside mechanism (usually top and bottom)
3. Press both tabs down simultaneously, this releases an extra portion of the sliding mechanism
4. Push the window open further, it should now tilt inward, bringing the exterior glass within easy reach
5. Clean the exterior surface from the safety of inside your home

Returning to Normal Position

1. Close the window most of the way while keeping the tabs depressed
2. Allow the tabs to click back into place, you should hear and feel them engage
3. Test that the window opens normally, if it only opens partially, you haven’t engaged the mechanism properly

Warning: Never lean out of windows to clean them, even if you don’t have easy clean functionality. For upper-floor windows without this feature, use an extension pole from inside or hire professional window cleaners. The risk of falling is never worth it.

When You Don’t Have Easy Clean

If your windows don’t have this mechanism:

• Use a long-handled squeegee and cloth from inside for the exterior surface
• Clean what you can safely reach from ground level
• Consider professional window cleaners for upper floors, they have the right equipment for working at height

Misting between the panes: what it means and what to do

This is the problem most readers arrive with. Windows are made as a sealed unit: two panes held apart by a spacer, with the gap filled with air or an insulating gas. Cleaning is not an option for that gap, because it was sealed in the factory, and the only way in is to break the unit.

This is perhaps the most frustrating double glazed window problem. You’ve probably landed on this article specifically because you’ve noticed condensation, fogging, or even dirt trapped between your window panes, and you’re wondering if there’s a way to clean it out.

The Hard Truth

If you have moisture or dirt between your window panes, your seal has failed. This isn’t something you can clean away with a cloth and some vinegar. The hermetic seal that kept the space between the panes airtight has developed a breach, allowing moisture to creep in.

Once moisture gets into that sealed space, it’s trapped there. On cold mornings, you’ll see it condense as droplets or fog. Even if it temporarily evaporates when the sun warms the window, it’s still there in the air between the panes, ready to condense again.

Why Seals Fail

Double glazed window seals can fail for several reasons:

• Age and wear. Seals gradually degrade over the years, which is why failures are more common on older windows.
• Poor installation. Windows that were not fitted or supported correctly put stress on the unit.
• Thermal stress. Repeated expansion and contraction as the temperature changes works at the edge seal.
• Water damage. Moisture reaching the seal from outside, for example from blocked drainage holes or failed external sealant, speeds up failure.
• Structural movement. Settlement in the building can stress frames and the units inside them.

In plain terms, fogging between panes happens when the seal breaks, moist outside air gets in, and the moisture condenses on the cold inner face of the outer pane. On warm days it may fade, but it is still in the cavity and returns when the temperature drops.

Condensation on the room side is a different problem

Mist on the room-facing glass, usually on cold mornings, is not a seal fault. It is household humidity meeting a cold surface. You can reduce it by ventilating for 10 to 15 minutes a day, using extractor fans when cooking and showering, keeping the heating consistent so there are fewer cold spots, running a dehumidifier if humidity stays high, and wiping the glass dry each morning to stop mould forming. If condensation is heavy despite good ventilation, there may be a wider damp problem in the home. Occasional condensation on the outside of the glass on clear, cold mornings can also happen with efficient glazing, and it is not a fault either. Only moisture or dirt inside the cavity points to a failed unit.

Temporary Solutions (They’re Truly Temporary)

Some DIY enthusiasts suggest temporary fixes to reduce the appearance of condensation. These don’t repair the seal, but they might buy you time before professional repair:

Using a Dehumidifier:

Place a dehumidifier near the affected window and run it regularly. This can help reduce the overall moisture in the room and may draw some moisture out if the seal breach is significant. However, it won’t fix the underlying problem.

Moisture Absorbers:

Silica gel packets, moisture absorber boxes, or “window snakes” placed along the bottom of the window might reduce visible condensation slightly. Again, this is masking the symptom, not fixing the cause.

Heat from Hairdryer or Space Heater:

Directing warm air at the window can evaporate visible condensation temporarily. By the time you’ve finished breakfast, it’ll likely be back.

Drilling a hole to insert a drying agent or flush the cavity is sometimes suggested online. Do not do it. The hole breaks the airtight seal that is left, lets in more moist air, risks cracking the glass and usually voids any guarantee, and it does nothing to fix the seal that failed in the first place.

Warning: Treat any advice to drill, pour or flush chemicals into the cavity as a reason to stop. Installers generally advise against it.

Permanent fixes

There are really only two proper fixes for failed seals. Which one makes sense depends on the condition of the frame, so ask a glazing company to look at both options.

Sealed unit replacement is the most common route. A glazier removes the existing glass unit, both panes together, and fits a new sealed unit in the frame you already have. It restores clarity and insulation, and is usually the better value if the frame is in good condition. The job is often done on a single visit.

Complete window replacement may make more sense if the frame is old or damaged, if several units have failed, or if you want better performance across the board. It gives you new frames, fresh seals throughout and a new guarantee.

Prices depend on the size, glass type and your area, so get at least two written quotes that say exactly what is included. Ask whether the guarantee on the original windows is still valid, since it may be.

Prevention Tips

While you can’t prevent seal failure forever, you can extend your windows’ lifespan:

• Keep rooms well-ventilated, excessive humidity speeds up seal degradation
• Maintain consistent indoor temperatures, extreme temperature fluctuations stress seals
• Clean regularly, removing dirt and grime from seals helps them last longer
• Address any leaks promptly, water damage around frames can compromise seals
• Inspect annually, catch small problems before they become big ones

Haze, scratches, stains and mould

Beyond condensation between panes, double glazed windows can develop other issues that affect their appearance and performance.

Removing Haze from Windows

A hazy appearance can occur on the accessible glass surfaces from:

• Residue from cleaning products
• Hard water deposits
• Built-up dirt and pollution
• Scratches that scatter light

If the haze is on the outside or inside surface you can reach:

1. Mix equal parts white vinegar and water in a spray bottle
2. Spray onto the affected glass
3. Wipe gently with a microfibre cloth in circular motions
4. For persistent haze, try a commercial glass cleaner designed for hard water deposits
5. Buff dry with a clean cloth

If the haze is between the panes:

This indicates seal failure. The haze is likely condensation residue or degraded desiccant material that’s trapped in the sealed cavity. This requires professional repair, surface cleaning won’t help.

Dealing with Scratches

Light scratches may be reduced, but deep scratches are usually permanent. Modern glass can also carry coatings that a polish could damage, so be cautious on any glass with a low-emissivity or self-cleaning coating, and stop if you are unsure. A glazing company can advise on a badly scratched pane, and replacing one unit may be a better result than repeated polishing.

For Light Scratches:

1. Purchase cerium oxide or iron oxide polish (available online or at specialist glass shops)
2. Apply a small amount to a soft cloth
3. Rub gently in circular motions over the scratch
4. Wipe clean and assess
5. Repeat if necessary

Tip: Test any scratch removal product on an inconspicuous corner of the glass first. While rare, some products can react poorly with certain glass coatings.

Prevention is Better:

• Remove rings and bracelets before cleaning windows
• Keep pets away from windows during cleaning
• Be careful with ladders and tools near glass
• Use proper window cleaning tools, not abrasive materials

Removing Specific Stains and Marks

Hard Water Stains:

Mix white vinegar with water (1:1 ratio), spray on, leave for 5 minutes, then wipe clean. For stubborn deposits, use a commercial lime scale remover designed for glass.

Bird Droppings:

Soak with warm water first to soften, then wipe gently. Never scrape when dry, you’ll scratch the glass. A dedicated bird dropping remover works well for regular problems.

Paint Splatters:

For water-based paint, warm soapy water should work. For dried gloss or emulsion, use a razor blade scraper held at a very shallow angle (almost flat against the glass) and work carefully. Always keep the glass wet while scraping.

Sticky Residue (from tape or labels):

On glass only, use a small amount of white spirit on a cloth, rubbing gently. Keep it off uPVC frames and rubber seals, where solvents cause damage, and wash the area thoroughly with soapy water afterwards.

Addressing Mould on Frames and Seals

Mould appears when there’s excess moisture and poor ventilation. It’s not just unsightly, it’s a health concern and indicates an underlying dampness problem.

To Remove Mould:

1. Mix 1 cup of white vinegar with 4 cups of hot water in a spray bottle
2. Spray the affected areas
3. Leave for 10 minutes
4. Wipe clean with a cloth
5. Dry thoroughly

For stubborn mould:

• Use a specialist anti-mould cleaner
• Ensure good ventilation during and after cleaning
• Wear gloves and a mask if the mould is extensive

Warning: Persistent mould around windows is a sign of ongoing moisture problems. While you can clean away visible mould, it will return unless you address the root cause, usually condensation from poor ventilation or heating.

For mould, our guides to removing mould from walls and what kills mould cover wider damp problems around windows.

Preventing Mould:

• Open windows regularly (even in winter, just for 10-15 minutes)
• Use extractor fans in bathrooms and kitchens
• Keep rooms adequately heated
• Wipe away condensation from window surfaces daily
• Use a dehumidifier if necessary

Kit worth buying, and what to look for in each

You do not need much, and none of this has to be expensive. These are the four things that make the biggest difference, with the main points to check before you buy.

• Window squeegee or squeegee kit. Look for a firm handle, a replaceable rubber blade that is straight and in good condition, and, for upstairs glass, an extension pole that attaches securely. A kit that includes a scrubber or washing sleeve saves buying a separate tool. Browse window cleaning kits or window squeegees and pick a blade width that suits your panes.
• Microfibre glass cloths. Look for a tight weave made for glass, often described as lint-free, and buy several so you can swap to a dry one for buffing. Wash them without fabric softener, which leaves a film that causes streaks. See microfibre glass cloths.
• uPVC cleaner. Choose one that names uPVC or plastic window frames and is non-abrasive. Test it on a hidden corner first and avoid anything with bleach or solvents. Warm soapy water is enough for light dirt, so this only matters for stubborn marks. See uPVC cleaners.
• Dehumidifier. Worth considering only if you have repeated room-side condensation. Look for a tank size and extraction rate that suit the room, a humidistat so it switches off at the right level, and an auto-restart or drain option. A dehumidifier reduces room humidity but does not repair a failed seal. See dehumidifiers.

How often to clean, and when to call someone

Regular maintenance keeps your windows looking great and helps you catch problems early before they become expensive repairs.

How Often Should You Clean?

Interior Glass: Monthly or as needed A quick wipe with a microfibre cloth takes just minutes and keeps your view clear.

Exterior Glass: Quarterly (at minimum) Urban areas with more pollution may need monthly cleaning. Rural locations might manage with twice yearly.

Frames and Seals: Quarterly A proper clean four times a year prevents buildup and helps you spot any developing issues.

Deep Clean: Twice yearly Spring and autumn are ideal times for a thorough clean of all window components.

Seasonal Considerations

Spring: Perfect time for a deep clean after winter grime. Check seals for winter damage.

Summer: Quick, regular cleans to remove pollen and dust. Easier to spot streaks in good light.

Autumn: Remove fallen leaves and debris from sills. Prepare windows for winter weather.

Winter: Wipe away condensation daily to prevent mould. Clean less frequently but monitor for problems.

Quick Clean vs. Deep Clean

Quick Clean (15 minutes):

• Wipe interior glass with microfibre cloth
• Quick frame dust-off
• Check for obvious issues

Deep Clean (30-45 minutes):

• Full interior and exterior glass cleaning
• Thorough frame cleaning
• Seal inspection and cleaning
• Sill and track cleaning
• Hardware check and lubrication

What to Avoid

Even with the best intentions, these common mistakes can damage your windows:

❌ Using abrasive materials, scratches are permanent

❌ Pressure washing, damages seals and can force water into frames

❌ Harsh chemicals, especially bleach, which ruins uPVC

❌ Scraping without liquid, creates scratches

❌ Reaching dangerously, upper windows need proper equipment

❌ Ignoring seal problems, they only get worse and more expensive

❌ Over-wetting wooden frames, causes swelling and rot

Keep Your Hardware in Good Condition

While you’re cleaning, spend a moment on window hardware:

• Hinges: Vacuum out dust, then add a drop of multi-purpose oil
• Locks: Keep mechanism clean and lubricated for smooth operation
• Handles: Wipe clean and tighten any loose screws
• Drainage holes: Check these aren’t blocked (they let water escape from the frame)

For more general window cleaning tips and techniques, our guide on the best way to clean windows covers additional methods you might find useful.

When a professional is the right call

Some window cleaning and repair tasks are definitely worth leaving to the experts.

Signs You Need Professional Help

For Cleaning:

• Windows above ground floor that you can’t safely access
• Very large or heavy windows that are difficult to manoeuvre
• Windows in awkward locations (above conservatories, over extensions)
• Regular maintenance for rental or commercial properties

For Repairs:

• Multiple windows with seal failures
• Condensation between any panes
• Cracked or damaged glass
• Frames showing signs of rot or significant damage
• Locks or mechanisms not working properly
• Windows that stick or won’t open/close properly

What Professionals Can Do

Window Cleaners:

• Access to high and difficult windows safely
• Professional-grade equipment (water-fed poles, safety harnesses)
• Faster, more efficient cleaning
• Regular maintenance contracts

Window Repairers:

• Seal repair or replacement
• Glass unit replacement
• Frame repairs
• Hardware replacement
• Professional diagnosis of problems

Fees for exterior cleaning vary with the number and height of windows, access and where you live, so ask for a written quote. Regular contracts often work out cheaper per visit than one-offs. Repairs vary with size and glass type.

DIY vs. Professional:

Consider professional help when:

• Safety is a concern (height, access)
• You lack the time or physical ability
• The problem is beyond your expertise
• The cost of mistakes exceeds the cost of professional service

DIY makes sense when:

• You can safely access all windows
• You enjoy the task
• You have the right tools and materials
• It’s routine cleaning rather than repairs

Short answers on vinegar, pressure washers and more

Is vinegar safe on double glazed windows and frames?

Diluted white vinegar is fine on the glass and on uPVC frames if you rinse and dry afterwards. Keep it off natural stone sills, which it can etch, and avoid leaving it to sit on rubber seals. If your frames are wooden, keep the cloth only barely damp.

Can I use a pressure washer on double glazing?

It is best avoided. A strong jet can force water past seals and into frames, and it can damage seals or loosen sealant. If you do use one, keep it on the lowest setting, wide fan and at a distance, and check the window manufacturer’s advice first. A hose, a soft brush and soapy water are safer.

Does mist on the outside of the glass mean the seal has failed?

Not usually. Efficient glass stays cold on the outer face, so on clear, cold, still mornings dew can form there, and it clears as the day warms. A failed seal shows as mist, droplets or dirt inside the unit, which you cannot wipe off from either side.

Can I pour hot water on cold windows to defrost them?

Avoid it. A sudden, large temperature difference can stress glass, especially if it has a chip or scratch. Use lukewarm water or a de-icing product made for glass, and wipe the frame and seal dry afterwards.

Can I use a steam cleaner on double glazed windows?

Be cautious. Steam can force moisture into frames and seals and can damage uPVC and rubber if held in one place. If you do use one, check the window manufacturer’s advice, keep the nozzle moving and away from seals, and dry everything afterwards.