After a professional window clean, everything looks better, more light, cleaner views, and that satisfying feeling of a properly maintained home. Then, a few weeks later, the grime starts creeping back. Some of it is unavoidable, but a surprising amount can be slowed significantly with the right habits and a bit of know-how about what actually causes windows to deteriorate.
Understand what's making your windows dirty
Before you can slow down the process, it helps to know what you're dealing with. In Sydney, window contamination typically comes from a few main sources:
- Hard water: Tap water and sprinkler water contain dissolved calcium and magnesium. When water evaporates, it leaves those minerals behind as a chalky white residue, called hard water spots or scale. Left long enough, these etch into the glass and become very difficult to remove.
- Salt spray: Within a few kilometres of Sydney's coast, ocean air carries fine salt particles that deposit on glass surfaces. This leaves a hazy film that diffuses light and gives windows a permanently grimy appearance even when they're otherwise clean.
- Pollution and traffic film: Suburban and inner-city homes accumulate a layer of fine particulate matter from traffic and combustion. This oily film mixes with moisture and bonds to glass, especially on north-facing windows that heat up during the day.
- Biological matter: Pollen, mould spores, bird droppings, and spider webs all add to the mix, and some of them, particularly bird droppings, etch into glass quickly if left to dry in the sun.
The most effective things you can do between cleans
1. Keep your sprinklers away from the glass
This is the single biggest preventable cause of window deterioration we see on Sydney homes. Garden irrigation systems are notorious for hitting exterior glass, and every cycle deposits a fresh layer of mineral-rich water. Over time, this builds into a thick calcified crust that takes serious effort (and sometimes professional restoration) to remove.
Adjust your sprinkler heads so they direct water onto the garden beds, not the building. It takes five minutes and will dramatically extend how long your windows stay clean.
2. Wipe bird droppings immediately
Bird droppings are acidic. On a hot Sydney day, a dropping left on glass for even a few hours can begin to etch the surface. Use a damp cloth with a small amount of dish soap and lift the dropping gently, don't scrub, as dry droppings contain debris that can scratch the glass. Rinse with clean water and dry with a microfibre cloth.
3. Rinse coastal windows after storms
If you live near the water, Bondi, Manly, Vaucluse, Cronulla, or anywhere along the northern beaches, a significant swell or strong easterly will coat your windows in salt residue. After a storm, a simple rinse with a garden hose (not tap water straight from a sprinkler onto hot glass) removes most of the salt before it concentrates and films over. You don't need to scrub, just rinse and let it drain off.
4. Clean the tracks and frames regularly
Dirty window tracks and frames are a constantly replenished source of contamination for your glass. Every time it rains, water washes through the tracks and carries mould, dirt, and grime particles down onto the glass below. A quick wipe of the frames and tracks every month or two significantly reduces how quickly the glass re-dirties.
5. Use a proper squeegee for touch-ups, not paper towel
If you want to do a light clean between professional visits, a good rubber squeegee with a cleaning solution is your best friend. Paper towel leaves lint fibres and microscopic scratches over time. A decent squeegee is about $50 and a mop about $40, and with a microfibre cloth to finish the edges that's the professional approach.
Avoid cheap spray-and-wipe products with heavy fragrances, they often leave a residue that actually accelerates the build-up of dust and grime.
What NOT to use on your windows
- ✕ Coarse steel wool or abrasive scourers. The pros use 0000 grade, the finest there is, for hard-water marks. Anything coarser scratches glass permanently
- ✕ Razor blades unless you're trained, they create micro-scratches at the wrong angle
- ✕ Ammonia-based cleaners on tinted glass, they degrade window tinting film over time
- ✕ Pressure washers at close range, they can crack seals and force water into wall cavities
- ✕ Cleaning in direct hot sunlight, the solution dries before you can squeegee it off, leaving streaks
