A skylight cleaning robot should be matched to your glass first, not your budget. Laminated glass needs lower wheel pressure, tempered glass tolerates tighter suction cups, and coated or low-e glass needs soft brushes and pH-neutral water. Get the match wrong and you void warranties or scratch a $40,000 roof panel.
Most buyers I talk to start with price. That is backwards. The glass on your roof decides almost everything else: how much suction the machine can pull, how hard the brush can press, and whether you even need water. Lingdu Intelligence builds three skylight cleaning robots — Lingkong K3, Lingyun Y3 and Lingfeng S1 — and each one lands on a different glass profile.
Why does glass type decide which skylight robot you buy?
Glass is not one material. A 6 mm single pane from 1998 behaves nothing like a 12 mm laminated unit with a low-e coating. When a robot presses a brush onto glass, it transfers load. Single glazing flexes; laminated glass with a 1.52 mm interlayer holds shape but the edge seals are the weak point.
Three numbers matter before you shortlist anything: glass thickness (millimetres), slope (degrees) and dead load the roof frame was rated for. A typical commercial skylight carries 0.5 to 0.75 kN/m² of design live load. Add a 28 kg robot plus a 12 L water tank and you are already using part of that margin.
| Glass type | Robot priority | Risk if ignored |
|---|---|---|
| Tempered, 6-10 mm | Moderate suction, standard wheels | Low |
| Laminated with PVB interlayer | Lower contact pressure, edge-aware path | Delamination at seals |
| Low-e / coated | Soft brush, pH-neutral water only | Coating haze, warranty void |
| Single glazing, older | Suction capped, no heavy water | Crack, fall-through |
What suction strength do you actually need?
Suction is measured in negative pressure, usually kPa. For a vertical curtain wall you want 8 to 12 kPa. For a horizontal or 15-degree skylight, gravity helps you, so 5 to 7 kPa is often plenty. More is not better. A machine pulling 15 kPa on 6 mm tempered glass is stressing the pane for no reason.
The Lingyun Y3 sits in the middle of that range and suits laminated atrium roofs. The Lingkong K3 runs higher suction and is built for steeper glass up to about 30 degrees and vertical facades. The Lingfeng S1 is the lighter unit for small pitched skylights where roof access is tight.
Here is the part vendors skip: suction fails gradually on wet, dusty glass. If your site has heavy dust from a nearby road or construction, plan on cleaning the cups every 40 to 60 minutes, not once a shift.
Which buyers should not buy a skylight robot?
If your roof has fewer than about 150 m² of accessible glass, the maths rarely works. You need roughly 80 to 120 m²/h of throughput to beat a rope crew on labour, and small sites never hit that because setup eats the day.
Fragile heritage glazing, hand-blown or leaded panels, is another no. No suction machine belongs on glass that is already cracking. Repair, then revisit. A building with a single flat 10 m² skylight should hire a crew twice a year and keep the money.
What should you check during a site survey?
- Measure slope at three points, not one — roofs settle and twist.
- Photograph every frame seal and edge; robots stop at obstacles your eye ignores.
- Confirm water access and where runoff can drain.
- Check wind exposure. Above 12 m/s most units must stop for safety.
- Note glass thickness from as-built drawings, not guesswork.
Read our fuller breakdown on selection by glass type before you sign anything, and compare what each model costs over five years in the total cost of ownership guide.
Do certifications actually matter here?
Yes, but for two reasons only. First, insurance: a CE-marked unit with an IP54 or better rating is far easier to get approved on a commercial roof. Second, spares. Certified machines tend to come from manufacturers that keep documentation, wiring diagrams and parts lists. Ask for the IP rating on the motor housing specifically, not the whole machine.
For outdoor skylight work on a wet roof, IP65 on the drive and pump is the sensible floor. Anything lower and you will be chasing corrosion in year two, especially on coastal sites where salt air attacks connectors and cup seals.
How much should you spend per square metre of glass?
As a rule, budget $25 to $45 per m² of accessible glass for the machine alone. Below that you are buying a toy with weak cups and plastic gears that will strip by month eight. Above $60 per m² you are paying for features most skylight roofs never use, like wall-climbing capability on rough concrete.
Spend the money on the boring parts instead: cup quality, edge sensors and a serviceable water pump. A robot that keeps its parts available for five years beats a cheaper one you cannot buy a squeegee for in year three.
What does commissioning look like on day one?
The first clean is always slower and always disappointing. Expect 40 to 50 percent of rated throughput for the first two weeks while an operator learns the roof layout and where the machine stalls. Plan a dry run with no water, then a wet run on one bay only.
Photograph the glass before and after, log the time, and write down every stall point. That log becomes your maintenance schedule and your training manual for the second operator. Skipping it is how fleets end up relying on one person who then goes on holiday.
Key Takeaways
- Glass type sets suction, brush pressure and water use — decide this before price.
- 5-7 kPa fits horizontal skylights; 8-12 kPa fits vertical curtain walls.
- Under 150 m² of glass, a robot usually will not pay back.
- Never run any suction robot on fragile or already-cracked glazing.
- Measure slope and seals in a survey; roofs are never as square as the drawings.