Before buying a skylight cleaning robot in 2026, ask seven questions: real-world throughput, suction-cup life, tether load rating, spare-part lead time, IP and CE documentation, training included, and who services it. Vague answers on lead time or certificates are the biggest warning sign.
Suppliers demo on ideal glass. Your building is the test. These questions separate a unit that lasts five years from one that becomes a spare-part orphan.
What is the realistic throughput on my roof?
Anyone can quote 600 m2/h. Ask them to justify it against your specific roof: slope, obstacle count, glass type, two-pass or one-pass finish. A good supplier will give a lower, honest number and explain the assumptions. If they will not commit to a figure for your roof, that is a red flag.
How long do the suction cups and brushes last?
Ask for replacement intervals and prices in writing. Cups typically last 8-18 months and brushes 3-6 months. If the supplier cannot name a price for a replacement cup set today, you will overpay when you urgently need one later. Budget these into your annual running cost.
- Cost of a full suction-cup set.
- Cost and lead time for brushes and squeegees.
- Filter part numbers and local availability.
What is the tether’s rated load?
This is a safety question, not a spec-sheet garnish. Fall arrest should be rated several times the robot’s weight, with an inspection schedule. Ask for the certificate. A supplier who shrugs at this has not thought about the roof you are putting it on.
What is the spare-part lead time?
A robot down for a month because a cup set ships from overseas costs more than the cups. Ask for lead times to your region for the top five wear parts. Anything over two to three weeks should push you to stock spares on site or look elsewhere.
Which certificates come with the unit?
| Question | Good answer | Walk-away answer |
|---|---|---|
| CE documentation | Declaration + test report | “It has a sticker” |
| IP rating | IPX4 or better, tested | Unstated |
| Battery listing | UL/UN38.3 docs | None |
| Spare lead time | Under 2-3 weeks | “Depends” |
| Training | Named days included | “It is easy” |
Who trains my team, and who fixes it?
Ask exactly how many training days are included, on site or remote, and who supports you in year two. A unit bought cheap with no service path becomes scrap the first time a pump fails. Get the service arrangement in the contract, not a verbal promise.
One more: ask to see the robot on a steep, wet panel. If they will not demonstrate grip under real conditions, assume the numbers are optimistic.
Who should refuse to buy?
Anyone whose supplier dodges the tether certificate, lead-time or training question. Those three omissions cause the costliest surprises. Also walk away if nobody on your team will own the maintenance log, because even the best robot degrades fast without it.
We answer all seven in writing for the K3, Y3 and S1. Start at the contact page.
What warranty and service terms should be non-negotiable?
Ask for a written warranty covering the pump, battery and control board separately, because their failure rates differ. A two-year pump warranty is worth little if the battery is only covered for six months. Also ask what void the warranty: water ingress, unauthorised repairs, or running outside the rated wind and slope.
- Pump and motor warranty: aim for 24 months.
- Battery warranty: at least 12 months or a stated cycle count.
- Service response time: days, not weeks.
- Warranty-void conditions stated in writing.
Why does the demo location matter?
A showroom demo on clean, flat glass proves nothing about your roof. Ask for a demo on a wet, angled panel with real dirt, ideally at your site. Watch how the robot behaves on a panel edge and how quickly the operator resets it. That ten minutes tells you more than a datasheet.
What contract terms protect you?
| Term | Why it matters |
|---|---|
| Spare-parts price list locked for 3 years | Avoids price shocks |
| Training days specified | Team can operate it |
| Service SLA in writing | Downtime is bounded |
| Tether certificate included | Insurer approval |
What is the one deal-breaker?
No service path. A robot is a machine that will need parts and occasional repair. If the supplier cannot name a local partner or a landed spare-parts route, the cheapest unit becomes the most expensive. Buy the service, not just the machine.
What does a fair delivery and install timeline look like?
Expect four to eight weeks from order to delivery for a standard unit, plus one to three weeks for anchors and training. Rail systems take longer, often eight to twelve weeks once installation is included. A supplier promising a rail install in a week is either rushing a load test or skipping it.
Anchor load testing alone can take a week to schedule with a certified contractor. Build that into your calendar before you tell tenants the roof will be clean by a certain date.
What questions reveal a weak supplier?
- They cannot name a local service partner.
- They will not put spare prices in writing.
- They dodge the tether certificate question.
- They push a demo on ideal glass only.
- They quote throughput without asking your roof.
How many quotes should you get?
Three, ideally on similar roofs you can visit. Ask each supplier the same seven questions and compare written answers side by side. The supplier who gives the least impressive throughput number and the most complete paperwork is often the most trustworthy, because they are telling you the truth about a hard job.
Key Takeaways
- Demand a realistic throughput number for your specific roof.
- Get cup, brush and filter prices in writing upfront.
- Ask for the tether’s rated load and inspection schedule.
- Check spare-part lead times to your region.
- Vague answers on certificates or training are walk-away signs.