There are three skylight cleaning machines worth considering: a pole-fed cleaning head for reach, a suction crawler for large accessible glazing, and a fixed rail unit for permanent atrium roofs. The right one depends on how much glass you have and whether a person can safely stand near it.
Most buyers shop by price and end up with the wrong class of tool. A €400 pole set and a €3,000 crawler are not competing products — they solve different problems on different roofs.
Type 1: The pole-fed cleaning head
A telescopic pole, 4-9 metres, with a water-fed brush head at the end, connected to a filtered water line. Simple, cheap, and surprisingly effective on glass you can reach from a safe place.
Throughput is 60-120 m² per hour depending on operator and height. On a 4-metre sunroom roof, one person cleans the whole thing in 20 minutes without a ladder. The catch: above about 9 metres, water pressure at the head drops and the pole becomes unmanageable in wind. Pole work also demands you stand in a position with a fall boundary, which on some roofs means harness and edge protection.
Who it suits: residential and small commercial roofs under 150 m², up to 9 metres, with a safe standing position. Who it does not: atria over occupied space or roofs where the standing area is itself the risk.
Type 2: The suction crawler
A wheeled chassis that grips glass with vacuum and walks the pane, spraying water and scrubbing. This is what most people picture when they search for a skylight cleaning robot.
Throughput runs 80-150 m² per hour on large flat panes and collapses to 30-50 m² per hour on panes under 1 m², because repositioning dominates. Pitch beyond 30-35 degrees degrades grip. Frame height over 30 mm stops most chassis.
Where it earns its keep: roof glazing of 200 m² or more with large panes and shallow frames, and atria where the alternative is scaffolding. Where it wastes money: 40 m² sunrooms, dense small-pane grids, patterned glass.
Two units worth studying if this is your class: our Lingyun Y3 review on a chassis built to clear raised kerbs, and the iGLASSBOT W200 SkyBot review for a lighter body on standard glazing.
Type 3: The fixed rail or gantry unit
Permanently installed on a structure above or beside the glass, running on rails. You do not carry it up; you press a start button. Throughput is high and labour is near zero, but installation is a construction project.
| Type | Cost | Coverage | Best case |
|---|---|---|---|
| Pole-fed head | $300 – 1,200 | Up to 9 m reach | Domestic sunroom, small retail |
| Suction crawler | $1,800 – 4,500 | 200 – 800 m² per shift | Commercial atrium, large roof glazing |
| Fixed rail unit | $25,000 – 80,000 installed | Thousands of m² over years | Airport, station, permanent atrium |
How much glass makes each type worth buying?
Rough thresholds from real installations. Under 100 m², a pole. 100-200 m², rent a crawler before buying one. Over 200 m² with four or more cleans a year, a crawler justifies its price within two seasons. Over 3,000 m² of permanent roof glass, a fixed rail system usually beats every alternative on lifecycle cost.
These are not sharp lines. They are the points where the labour savings stop being a rounding error, and they move with local wage rates. In the UK and Germany, the crawler threshold drops closer to 120 m². In Poland or the Gulf, it sits higher.
Does the glass type rule out any option?
Yes — more often than buyers expect.
- Patterned or textured glass: rules out suction crawlers. The seal cannot hold, and the brush leaves residue in the pattern.
- Self-cleaning coated glass: rules out abrasive pole brushes and dry crawler passes. Both strip the coating faster than rain would.
- Frameless bonded glass: rules out heavy crawlers. Check glue line load with the glazier before putting 5 kg on it.
- Polycarbonate and acrylic roofing: rules out almost every machine. These scratch; a pole with a soft pad and clean water is the only sensible option.
What does a typical cleaning system look like in operation?
For a 600 m² retail atrium: two-person crew arrives, one anchors the safety tether at a fixed roof point, the other places the crawler and runs it. Roughly 45 minutes per bay, four bays per morning, water from a 20-litre tank topped up twice. Total elapsed time around five hours including setup and teardown.
Compare with a rope crew on the same glass: four hours of rigging, half a day of cleaning, and a thousand euros of access cost. The economics are not subtle at this size — which is why commercial buyers stop asking whether robots work and start asking which robot.
How do you avoid buying the wrong one?
Measure three things before you shortlist: total glass area, the tallest frame or kerb anywhere on the roof, and the steepest pitch. Then write down where a person can stand safely. That last item is what separates a pole job from a crawler job, and it is the one buyers skip.
If the answers point to a crawler, start with comparing the robot against pole work, then use the review archive to narrow models by glass compatibility.
Key Takeaways
- Three classes exist: pole-fed head, suction crawler, fixed rail unit — pick by glass area and standing safety.
- Below 100 m², a pole is the answer. Crawlers justify purchase above roughly 200 m² with four cleans a year.
- Crawler throughput collapses on panes under 1 m² because repositioning dominates.
- Patterned, frameless bonded and polycarbonate roofs rule out most machines outright.
- Fixed rail systems only make sense on permanent, large-area roofs designed for them.