Skylight cleaning machines fall into three families in 2026: suction climbers for flat glass under 30 degrees, tracked gantry units for large canopies, and water-fed pole kits; the canopy size and pitch pick the family before price does.
Every skylight cleaning machine on the market in 2026 belongs to one of three families. They differ in how they hold to glass, how much canopy they cover in a shift, and what they cost. Choosing within a family is a detail decision. Choosing the wrong family is why machines end up stored in a plant room.
What are the three families?
| Family | Holds by | Pitch limit | Coverage per shift | Price |
|---|---|---|---|---|
| Suction climber | Vacuum seal | 30-35° | 150-300 m² | $5,000-12,000 |
| Tracked gantry | Rails or module edge | 0-25° | 800-2,000 m² | $12,000-45,000 |
| Water-fed pole kit | Nothing (manual) | Any reachable | 200-400 m² | $400-1,500 |
One field observation before the table’s numbers are trusted. Coverage figures assume the canopy has no plant screens, cable trays or roof-mounted air handling units within 1.5 m of the glass edge. In practice about a third of commercial canopies have exactly that, and the first metre of every run becomes a manual job. Measure the clear margin before you accept any per-hour figure.
Note the pitch column. The gantry family covers more ground but handles less slope, because tracks need a surface to sit on rather than a surface to stick to. That inversion confuses a lot of buyers who assume the more expensive machine does everything.
Which family fits a typical atrium canopy?
Suction climber, usually. Atrium glazing is often 15-30 degrees, framed, and 200-600 m² — exactly the climber’s comfort zone. Typical coverage on a 400 m² canopy is one full cycle in 2.5-4 hours including setup, which means one shift per clean with time left over for the lower windows.
The gantry family only wins when the canopy is 800 m² or larger and roughly flat, or when it is a sawtooth or barrel-vault roof where a tracked unit can follow a rail. On a barrel vault above 300 m², gantry units are the only practical option because a climber’s seal cannot follow the curve continuously.
When is the cheap option the right one?
More often than the industry likes to admit. Below about 150 m², a water-fed pole kit with a deionised filter does the job in 40-90 minutes, costs under $1,500, and has no consumables beyond resin. It cannot reach an atrium over a 12 m void, and it cannot climb a 35-degree pitch safely. Everything else, it handles.
For a school with four skylights, a pole kit is the correct purchase. So is it for a small retail unit with a 60 m² canopy. The robot sellers will disagree, and they are selling a different product to a different buyer. All skylight robot reviews on this site include the pole comparison so you can see where the crossover sits.
How do the families compare on running cost?
A climber on weekly duty costs $600-1,200 a year in seals, belts and water filtration. A gantry unit runs $900-1,800, mostly tracks and idler wheels. A pole kit costs $80-200 in resin and replacement heads. That ordering reverses the purchase price order, which is why five-year cost analysis sometimes favours the cheapest option even on large canopies — if labour is cheap.
One specific risk with climbers on skylights: the recovery tank. On a 25-degree canopy, water that should be collected runs back toward the lower seal. Buyers see streaks and assume brush problems. The cause is usually the drip angle. Units designed for vertical glass simply do not collect on a slope — we cover that in our Lingfeng S1 review, which was tested on pitched glazing rather than a window.
What should be settled before you buy?
- Exact canopy area and the geometry of the frames, not a photo.
- Pitch at the steepest point, and whether that point has a mullion cap.
- Access route and carrying weight; a 22 kg gantry does not go up a ladder.
- Water supply and drainage near the canopy.
- Who empties the recovery tank and how often.
The last item sounds minor. On a 30 m high canopy with no lift, it decides whether the machine gets used weekly or quarterly.
How long does a full cycle take?
On a 400 m² framed atrium canopy at 22 degrees, a climber does a wet pass at 90-140 m² per hour including repositioning. That is a 3-4 hour cycle with setup. The same canopy with a gantry unit runs 300-500 m² per hour but needs 45-70 minutes of deployment, so it only wins on a single large clean.
The practical result: for one clean a month, the two families come out roughly equal at 600 m². Below that, the climber wins on setup. Above 1,000 m², the gantry wins on coverage. Between those, put a stopwatch on your own access route before trusting anyone’s per-hour figure.
Consumables differ more than coverage does. A climber needs a seal every 800-1,200 hours and belts yearly; a gantry needs track replacement every 2-3 seasons, the single largest recurring cost in that family. Ask for a three-year parts schedule rather than a list price and compare totals.
Key Takeaways
- Three families: suction climbers for 30-35 degree flat glass, tracked gantries for large flat canopies, pole kits for small ones.
- Gantry units cover 800-2,000 m² per shift but handle less pitch than a climber — the trade runs opposite to price.
- Below about 150 m², a water-fed pole kit at under $1,500 is the correct purchase.
- Running costs run $600-1,200 a year for climbers and $900-1,800 for gantries.
- Streaks near the lower edge on a pitched canopy are usually a drip-angle problem, not the brush.