Ultrasonic spray vs. damp cloth: which cleans better?
One point that surprises many people: robotic window cleaners work better with low humidity (a fine mist/spray) because they need to maintain suction. In tests and practical impressions, the spray is usually a light "mist," and the cloths are only slightly damp at the end.
1) Damp cloth (without automatic spray)
How it works:
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You manually dampen the cloth/microfiber.
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The robot performs the friction and "polishing"
✅ Advantages:
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simple and economical
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Fewer components (fewer things to break)
⚠️ Limitations:
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If you over-wet it, you may increase the risk of marks and reduce suction.
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It requires more "hands-on" work from the user (hygiene and changing cloths).
2) Spray/mist (including ultrasonic): why it helps
In usage experiments, the fine mist helps dissolve light dirt and reduce streaks without soaking the glass.
Some models and manuals highlight spray/atomization systems and even ultrasonic spray as features that allow for frequent maintenance.
✅ Advantages:
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More controlled and uniform humidity
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fewer “risks” in maintenance (when cloths are clean)
⚠️ Limitations:
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For heavy dirt on the outside (dried mud, debris), robots may not provide a "deep clean" and you may need to pre-clean.
3) How to avoid marks (a simple routine that works)
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First pass : clean, slightly damp cloth (or light spray mode)
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Second pass (polishing) : dry/clean cloth
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Change the cloths when they get dirty (dirty cloth = marks).
This aligns with the reality that quality can vary by model and glass condition — and that sometimes more than one cycle is needed.
FAQ
Can I use a lot of detergent and leave the glass very wet?
It's not ideal: robots tend to work "drier," with a light mist, to maintain suction.
Is ultrasonic spray worth it?
It especially helps maintain and maintain moisture consistency, reducing the risk of marks with regular use.