A window cleaning robot only cleans as well as the pad strapped to its underside. The laser navigation, the suction seal, and the dual spray system all matter, but a dirty or worn pad on the WD8 will leave streaks and smears no matter how well the rest of the machine is working. Pad care gets overlooked because it feels like a small, almost cosmetic detail compared to setup or navigation, but it is the single most common reason people end up disappointed with results that were actually well within the robot's capability. This guide covers how the WD8's pads work, how to clean them properly after use, and the signs that tell you it is time to replace rather than clean them again. None of it takes long, and most of it becomes routine within a couple of cleans, but skipping it consistently is what turns a good window cleaning robot into one that seems to be underperforming.
What the WD8's Cleaning Pads Actually Do
The WD8 holds itself against glass using suction, rated at 3,000Pa on a glass surface, while its dual spray system wets the surface and the attached pad does the actual wiping as the robot moves across the window in a laser-guided path. The pad is doing two jobs at once: lifting dirt and grime from the glass, and maintaining even contact so the suction seal stays reliable as the robot travels.
A pad loaded with old residue does both jobs badly. Built-up grime reduces how much new dirt the pad can actually lift, so you end up with the spray wetting the glass and the pad redistributing dirt rather than removing it. It can also change the surface texture of the pad slightly, which affects how evenly it sits against the glass during the suction-guided pass.
Because the WD8 includes a 40-minute backup power supply specifically so it does not lose suction and fall if mains power is interrupted, keeping the whole system in good working order, including the pads, is not just about clean results. It is part of what keeps the robot securely attached to the glass throughout a full clean.
It is worth thinking of the pads as a working part of the robot's safety system rather than a purely cosmetic accessory. A robot climbing and traversing a vertical pane of glass depends on consistent contact between the pad and the surface, and anything that disrupts that contact, whether it is grime, wear, or an improperly fitted pad, has knock-on effects beyond just cleaning quality. This is one of the reasons pad maintenance is worth treating as a routine step rather than something to get to eventually.
How to Clean the Pads After Each Use
Remove both pads from the robot once a clean has finished, rather than leaving them attached between uses. Rinse them under running water to lift loose dirt and any dried spray residue, working the fabric gently with your fingers rather than scrubbing hard, since aggressive scrubbing can wear down the pad's fibres faster than normal use would.
Squeeze out excess water rather than wringing the pad tightly, and lay both pads flat to air dry completely before storing them or reattaching them to the robot. A pad that goes back onto the robot still damp is more likely to pick up dust and grit during storage, which then gets ground into the fabric the next time it is used.
Do this after every clean, not occasionally. It takes a couple of minutes and is the single biggest factor in how long a pair of pads lasts before they need replacing.
It also helps to check the pad's fabric while it is off the robot, rather than only glancing at it while it is still attached. Wet fabric under a running tap makes it much easier to spot early thinning or small tears than a quick visual check on the robot itself, where the pad is partly obscured by the housing. A minute spent inspecting the fabric properly during the rinse is often when early wear first becomes noticeable, well before it would show up as a performance issue during an actual clean.
Deep Cleaning and Dealing with Hard Water Marks
A weekly rinse under running water is usually enough for normal dust and light grime, but homes with hard water often see a white, slightly chalky residue build up on the pads over time from mineral deposits in the spray water. When this happens, a warm hand wash with a small amount of mild dish soap, followed by a thorough rinse to remove all soap residue, will usually clear it.
Avoid fabric softener, bleach, or strong detergents on the pads. Fabric softener in particular can leave a coating on the fibres that reduces how well the pad grips dirt on subsequent cleans, which defeats the purpose of washing it in the first place. A plain rinse or a mild soap wash is all the pads need.
If hard water marks keep reappearing quickly after washing, consider using filtered or distilled water in the WD8's spray reservoir instead of tap water. This reduces the mineral content reaching the pads and the glass in the first place, rather than needing to be cleaned off after the fact.
Once pads are fully dry, store them somewhere flat and dust-free rather than folded or bundled together in a drawer with other cleaning supplies. Folding a slightly damp pad, even one that feels dry to the touch, can encourage mildew to develop in the fold over time, which is both unpleasant and difficult to fully remove afterwards. A simple flat storage spot near where you keep the robot itself is usually enough.
When to Replace the Pads
Pads are consumable, and no amount of careful washing extends their life indefinitely. A few signs reliably indicate it is time for a new pair rather than another wash.
Fraying or Thinning Edges
Once the edges of a pad start to fray or the fabric visibly thins in patches, its ability to maintain an even seal against the glass during suction-guided travel starts to drop. This is usually the first visible sign of wear, well before the pad stops working entirely.
Persistent Streaking Despite Clean Pads
If you have just washed the pads and the WD8 still leaves streaks it did not leave when the pads were newer, the fabric itself has likely lost some of its lifting capacity through repeated use, rather than needing another wash. This is the clearest sign that washing has reached its limit.
Reduced Grip or Slipping During Cleans
If you notice the robot seeming less securely seated during a clean, or hear it labouring in a way it did not previously, worn pads can be a contributing factor alongside suction strength itself. Replacing the pads is a simple first troubleshooting step before assuming a deeper suction problem.
Discolouration That Doesn't Wash Out
A pad that has taken on a permanent grey or yellowed tinge, even immediately after a wash, has usually absorbed grime deep enough into the fibres that surface cleaning cannot reach it. This is different from a temporary hard water mark, which lifts with a proper wash. If the discolouration remains consistent wash after wash, treat it as a sign the fabric has reached the end of its useful life rather than continuing to wash a pad that looks the same every time regardless of effort.
Genuine pad wear like this is not usually a fast decline. Most households get a reasonable number of cleans out of a pair before replacement, with actual lifespan depending heavily on how consistently they are rinsed after each use and how hard the local water is.
Households running the WD8 frequently, such as multiple times a week on ground-floor windows or a conservatory, will naturally reach these wear signs sooner than a household using it monthly on a single upstairs window. This is not a fault of the pads or the robot. It simply reflects total contact time with glass and grime, in the same way a mop head used daily wears faster than one used occasionally. Matching your expectations for pad lifespan to your actual usage pattern, rather than a single fixed number, gives a more realistic sense of when replacement is likely.
Frequently Asked Questions
How often should I replace the WD8's cleaning pads?
There is no fixed schedule that applies to everyone, since it depends on how often you run the robot and how consistently you rinse the pads after each use. Rather than replacing on a calendar basis, watch for the physical signs of wear described above: fraying edges, thinning fabric, or streaking that persists even on freshly washed pads. Households that rinse pads after every single use typically get noticeably more cleans out of a pair than those who leave pads attached and unwashed between uses.
Can I use regular household cloths instead of the official pads?
This is not recommended. The WD8's pads are designed to work with the robot's specific suction and spray mechanism, and a substitute cloth may not maintain the same seal against the glass or fit securely enough during operation. Given that the robot relies on a consistent seal to stay attached to the glass safely, using pads designed for the machine rather than an improvised substitute is the safer and more reliable option.
What if a pad tears while I'm washing it?
Stop using that pad immediately and replace it before the next clean. A torn pad can affect the suction seal unevenly, and running the robot with damaged pads on a vertical glass surface is not worth the risk to either the robot or the window. Keep a spare pair on hand if the WD8 is part of your regular cleaning routine, so a torn pad does not mean skipping a scheduled clean entirely.
Why does one pad seem to wear faster than the other?
This usually comes down to how the robot's path is weighted across a given window, or a slight difference in how each pad was rinsed and dried after previous cleans. It is not a sign of a fault. If the difference becomes pronounced, replacing both pads together rather than one at a time keeps suction and cleaning performance even across the whole pass.
Can I wash the pads in a washing machine?
Hand washing is the safer option. A washing machine's agitation and spin cycle are considerably more aggressive than the gentle rinsing the pads need, and this can accelerate fraying and thinning well beyond what normal use alone would cause. A quick hand rinse after every use, with an occasional mild soap wash, is both simpler and gentler on the fabric than a full machine cycle.
Do I need to clean the pads if the WD8 hasn't been used in a while?
Yes, before the next use rather than after. Pads left attached to the robot in storage can pick up dust, and pads stored loose can flatten or pick up odours if they were not fully dry when put away. A quick rinse and full air-dry before reattaching is worth doing even if the pads look clean, simply to remove any dust that settled during storage.
How do I know if a pad is fitted correctly before a clean?
A properly fitted pad should sit flat against the underside of the robot with no visible bunching, gaps, or loose edges hanging free. Run a hand over it once attached to check it feels even all the way round. A pad that is bunched on one side or not fully seated can affect the suction seal unevenly during the clean, which shows up as patchy results or an uneven pass across the glass. Taking a few extra seconds to check the fit before starting is a simple habit that avoids having to redo sections afterwards.
Final Thoughts
Pad care is a small habit that has an outsized effect on how well the WD8 performs. Rinse after every use, air dry fully before storing or reattaching, and watch for fraying, thinning, discolouration, or persistent streaking as your signal to replace rather than wash again. It is a two-minute routine that pays off in cleaner glass and a robot that stays reliably seated during every pass, clean after clean, for as long as the pads themselves hold up. Replacement pads and other accessories are available in our accessories range, and if you are still deciding whether a window cleaning robot fits your routine, the WD8 product page and our wider window cleaning robot collection are good places to compare options.
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