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Cleaning double glazed windows is straightforward once you know what makes double glazed windows different from single glazing: two glass panes sealed as one unit, frames built for a thicker unit and, on quality products, low-e coatings. A few techniques and product choices matter more than they would on a basic window.
Most cleaning problems come down to the wrong products, the wrong technique or the wrong timing. The tips below cover all three, plus how to handle the common problems and the regular checks that keep your windows performing.
If you’re also considering upgrading or replacing your windows, our guides to double glazed sliding windows and double glazed awning windows cover how each type performs and what to look for when specifying a new window — useful reading if maintenance has prompted you to think about whether your current windows are still the right fit.
The glass panes themselves are cleaned in the same way as any quality glass, with some important caveats around coatings. Many double glazed windows include a low-emissivity (low-e) coating that affects thermal performance. Soft-coat low-e sits on an inner face within the sealed unit, where normal cleaning can’t reach it. Hard-coat low-e is more durable and is sometimes on the room-side face of the glass, so avoid abrasive pads and scraper blades on any window where you’re not sure which type you have.
What can be at risk is the edge seal of the insulating glass unit (IGU) — the hermetic, airtight seal formed around the perimeter of the unit during the manufacturing process. Harsh chemicals, particularly solvent-based cleaners, can degrade silicone and polysulfide seal materials over time if they’re regularly applied near the glass edge. Most standard glass cleaners won’t cause a problem with occasional use, but concentrated chemical cleaners and strong solvents should be avoided.
The frames have their own cleaning requirements. uPVC frames need only mild soapy water; avoid solvents and abrasive cream cleaners, which can dull or mark the surface. Powder-coated aluminium frames are durable but not impervious to strong chemicals or highly abrasive materials either.
If you’re noticing persistent condensation on the glass, it’s worth understanding that this is often linked to indoor humidity and ventilation rather than a cleaning issue. This guide on double glazing, condensation, and mould explains why it happens and what practical steps help reduce it over time.
Getting the tools right makes the difference between a clean, streak-free result and a frustrating smeared mess.
The following tools effectively cover most cleaning situations.
Warm water with a small amount of dish soap is effective, inexpensive, and safe for glass, frames, and seals. Avoid high-concentration detergents, bleach-based cleaners, solvents, and anything abrasive. A diluted white vinegar solution is also effective for mineral deposits and water staining: around one part vinegar to ten parts water for light haze, up to one part to four for heavier deposits. It isn’t appropriate for stone surrounds or certain frame finishes, so test in an inconspicuous area first. For stubborn grease or sticker residue on the glass itself, a little methylated spirits on a lint free cloth works well; keep it off the seals and frames.
A garden hose for rinsing is useful but not essential. For upper-storey windows, an extendable squeegee or a water-fed pole system (available from most hardware stores) allows safe reach without a ladder for many installations.
Abrasive sponges or scourers, steel wool, concentrated solvent-based products, pressure washers at high pressure (low-pressure rinsing is fine, but high-pressure directed at the frame or glass edge can force water past seals and into wall cavities), and window cleaning products with added wax that can cause smearing on glass rather than polishing it.
Working through these steps in order yields the best results and avoids common mistakes that cause streaking, scratching, or residue.
Cleaning windows in direct sunlight causes the cleaning solution to dry on the glass before you can wipe or squeegee it off, leaving streaks and residue that require re-cleaning. Where the weather permits, choose overcast days or times when the window is in shade; early morning or late afternoon works well for most windows. Avoid hosing sun-heated glass with cold water, as the sudden temperature change adds thermal stress to the glass.
Before applying any water or cleaning solution, remove loose dust, cobwebs, and surface grit with a soft, dry brush or cloth. This is particularly important for the tracks and frame channels, where any grit left behind can scratch glass or frames once it’s mixed into the wet cleaning process.
On exterior windows, a light rinse with a garden hose (gentle pressure) at this stage removes loose surface dirt effectively before scrubbing begins.
Apply your warm water and dish soap solution to the glass using a sponge or soft cloth. Work from the top downward so dirty water runs down away from cleaned areas. For heavily soiled glass — pollen, insect residue, bird marks, salt spray in coastal areas — let the solution sit for a minute before working it.
Use light to moderate pressure. The point is to dissolve and loosen the dirt, not to scrub it. Excessive pressure on glass isn’t necessary and can be counterproductive if grit is still on the surface.
This is the technique that transforms the result from passable to genuinely clean. A good squeegee removes cleaning solution completely and uniformly in a way that cloths rarely achieve.
Start at the top corner and work in horizontal strokes across the pane, or use an S-stroke technique if you’re comfortable with it. Wipe the squeegee blade with a clean chamois or microfibre cloth between each stroke — this prevents dirty solution from one stroke from being dragged back across the cleaned glass in the next.
On the final stroke, a chamois or microfibre cloth is run along the bottom edge of the glass to catch any drips or runs.
Any remaining moisture at the glass edges, in frame channels, or around the perimeter of the unit should be wiped with a dry lint free cloth. Pay particular attention to the junctions between the glass and the frame — accumulated moisture in these areas is where algae and dark staining can develop over time.
For uPVC or powder-coated aluminium frames, a warm soapy water solution applied with a soft cloth is all that’s needed. Wipe down the frame faces, edges, and reveals. Rinse with clean water and dry with a cloth.
Sliding window and door tracks accumulate grit and debris that interfere with smooth operation. Use a vacuum to remove loose debris first, then a damp cloth or an old toothbrush to clean the channel. A light application of silicone spray (not oil-based lubricant, which collects dirt) on the rollers and track after cleaning helps maintain smooth operation.
Most cleaning challenges with double glazed windows fall into a small number of recurring categories. The following covers the most common ones and how to address each effectively.
In areas with hard water, or on coastal properties where salt spray leaves salt deposits and minerals on glass, standard washing may not fully remove the white haze or cloudy areas that develop. A diluted white vinegar solution applied to these areas and allowed to sit for several minutes before washing off dissolves calcium and mineral deposits effectively. For stubborn cases, a proprietary mineral deposit remover for glass — available at hardware stores — works well. Do not use abrasive cleaners or scrub with any rough material, which will scratch the glass surface.
Interior glass surfaces often collect fingerprints, cooking grease in kitchens, and general contact marks. A small amount of dish soap solution on a microfibre cloth, followed by a squeegee or a clean, dry cloth, removes these effectively. The key is ensuring the final step removes all detergent residue — any film left by the cleaning product is what causes smearing.
This is something cleaning cannot fix, and attempting to clean between the panes is not possible on a factory-sealed IGU. If you’re seeing fogging, haze, or white deposits between the panes — which don’t wipe off the surface because they’re inside the sealed unit — this indicates a failed seal. The unit must be replaced; the condensation is within the cavity, not on the glass surface. A failed unit also loses much of its energy efficiency and noise reduction, which can show up in higher heating and cooling bills. See this as a maintenance signal rather than a cleaning problem.
Condensation on the room-side surface is different. Untreated condensation that accumulates around windows increases the risk of mould growth and property damage, so wipe it away and reduce indoor humidity: open windows when you can, and run exhaust fans while cooking and showering.
For upper-storey windows that are difficult to reach safely, extendable water-fed poles with a microfibre pad attachment allow cleaning from ground level for many window heights. These use clean (often deionised) water fed through the pole, eliminating streaking because there’s no detergent residue left to dry on the glass. They’re available for purchase or hire from hardware stores and cleaning suppliers, and they’re worth considering for any home where upper-window access is a recurring challenge.
In dusty inland and regional areas, windows accumulate a fine dust film that benefits from rinsing before any wiping to avoid the dust acting as an abrasive. After bushfires or nearby agricultural burning, ash and fine particulate on glass should be rinsed thoroughly before any cloth contact — ash particles are abrasive enough to create micro-scratches on glass if wiped dry.
In coastal areas, regular cleaning is more important because salt deposits on glass and frames accelerate corrosion of hardware if they accumulate. Monthly cleaning is more appropriate than quarterly for coastal properties. Salt also combines with other airborne residues to create deposits that become harder to remove the longer they’re left.
High ultraviolet (UV) conditions bake any residue or film left on glass into the surface faster. In Queensland and other high-UV states, leaving cleaning product residue on glass is more likely to create a baked-on film than in milder climates. Thorough rinsing is particularly important.
A handful of recurring errors account for most poor results in window cleaning. These are the ones you most need to know before you start.
Full afternoon sun causes the cleaning solution to dry almost immediately, creating streaks that require re-cleaning. Work in shade or on overcast days for consistently better results.
Scourers, rough cloths, and steel wool on glass or frames cause permanent micro-scratching that’s visible when light catches the surface. Even minor scratching on glass cannot be reversed.
Concentrated bleach or solvent-based products applied near the glass edge risk degrading the IGU seal material over time. Occasional exposure to standard diluted cleaners is unlikely to cause problems; regular heavy application near the seal perimeter is not.
Pressure washing directed at window frames or glass edges can force water past frame seals into wall cavities and around the glass edge. Low-pressure garden hose rinsing is fine; high-pressure washing is not.
Cleaning tracks without vacuuming the loose debris out first just moves abrasive grit around the channel rather than removing it. Always vacuum before wiping.
For most suburban Australian homes, cleaning double glazed windows two to four times a year maintains them well. Spring and autumn cleanings address the accumulated pollen, dust, and residue of the preceding seasons. More frequent cleaning is appropriate for coastal properties (monthly or every six weeks), homes in dusty environments, or homes with significant tree coverage that regularly deposits pollen, leaf matter, or bird residue on glass.
Use each clean as a chance for regular maintenance. Check seals for gaps or cracking, test that locks and handles work smoothly, and look for early signs of fogging between the panes. Early detection through these regular checks makes it easier to fix small problems before they affect performance.
Cleaning double glazed windows well comes down to gentle products, the right technique and the right conditions. Warm soapy water, a good squeegee, a lint free cloth and care around the seals keep the glass clear and the frames in good condition for years, and the common mistakes (sun, abrasives, skipping the squeegee) are easy to avoid.
Regular care beats occasional heavy cleaning. Well maintained windows keep their seals, coatings and hardware working longer and lift your home’s appearance too.
If you spot a failed seal, fogging or hardware that no longer works, APS Double Glazing offers expert support across Melbourne, from repairs and unit replacement to new uPVC double glazed windows.
Use warm water with a small amount of dish soap, apply with a soft sponge working from the top down, then squeegee with horizontal strokes, wiping the blade between each pass. Cleaning in shade rather than direct sun prevents the solution from drying before you can squeegee it off, which is the most common cause of streaking.
Yes, a diluted white vinegar solution (one part vinegar to four parts water) is effective on glass, particularly for mineral deposits and water staining. Avoid using it on aluminium frames without testing first — it’s generally fine on powder-coated finishes but can be problematic on some anodised finishes or on stone surrounds adjacent to the window.
You can’t — and shouldn’t attempt to. The two panes of a factory-sealed double glazed unit are sealed together permanently with a hermetic seal. If you’re seeing fogging, haze, or deposits between the panes, this indicates the seal has failed, and the unit needs to be replaced.
Two to four times a year for standard suburban homes. More frequently for coastal properties (monthly to every six weeks), dusty environments, or homes with heavy tree coverage. Regular light cleaning is more effective and less damaging than infrequent heavy cleaning.
Low-pressure rinsing with a garden hose is fine. High-pressure washing is not recommended — it can force water past frame seals into wall cavities and around the glass edge. The glass doesn’t require pressure to clean effectively.
Vacuum loose debris first, then use a damp cloth or old toothbrush to scrub the track channel. Rinse and dry. A light application of silicone spray (not oil-based) on the track and rollers after cleaning helps maintain smooth operation. It doesn’t attract additional dirt the way oil-based lubricants do.
Abrasive sponges or scourers on glass or frames, concentrated solvent-based or bleach-based cleaners near the glass edge seal, high-pressure washing, cleaning in direct sunlight, and using materials or cleaners with wax additives that leave a film on glass. Regular exposure to harsh chemicals near the IGU perimeter seal can degrade the seal material over time.