Quick answer: A robot window cleaner works on any window whose individual pane of glass is larger than the robot itself. In UK terms: uPVC casements, fixed picture windows, bifolds, sliding doors, tilt-and-turns, skylights and most modern sash windows are all fine. The genuine exclusions are Georgian-bar and leaded windows (each little pane is smaller than the robot) and glass in poor repair. Frames, hinges and openings don't matter — the robot lives entirely on the glass.
British housing stock is a museum of window styles, so "will it work on my windows?" is the right question to ask before buying. Here's the honest compatibility list, type by type.
The one rule that decides everything
A suction robot needs a continuous flat sheet of glass bigger than its own footprint — roughly an A3 sheet of paper as a mental yardstick. It detects frame edges and turns back; it doesn't climb over bars or transoms. So the question is never "what style is the window?" but "how big is each uninterrupted pane?"
Works brilliantly ✅
- uPVC casement windows — the standard modern UK window. Each casement is one clean pane. Perfect.
- Fixed picture windows and gable glazing — big, sealed, often high up: this is the robot's home turf, since nothing else cleans them safely from inside.
- Bifold and sliding patio doors — huge panes at ground level; the robot does in minutes what takes you half an hour of reach-and-streak.
- Tilt-and-turn windows — doubly good: tilt them inward and the robot (or you) can reach the outside face from indoors.
- Velux and skylights — robots grip on sloped and overhead glass; full skylight guide here.
- Conservatory panels and greenhouse roofs — large panes, yes; small Victorian overlapping panes, no.
Works with a caveat ⚠️
- Sash windows — modern sashes with one pane per sash: fine, treat each sash as its own job. Period sashes divided into "six over six" small panes: the robot won't fit. A quick tape-measure check against the robot's dimensions settles it.
- Frameless glass (balustrades, frameless corners) — good robots handle edges without frames using edge-detection; the CleanBot R1 does this as part of its 8-layer safety system. Always anchor the safety rope on frameless glass.
- Obscured bathroom glass — smooth satin/acid-etched: usually fine. Deeply textured patterns: the suction seal can't form — see the full can't-clean list.
Genuinely not suitable ❌
- Georgian-bar windows where the bars are real dividers creating small panes. (Stick-on "astragal" bars between the glass sheets are fine — the outer surface is one big pane. Check whether you can feel the bars: raised on the outside = real dividers.)
- Leaded and stained-glass windows — small panes, raised cames, irreplaceable glass. Hand-clean only.
- Cracked or loose glass — never put suction on damaged panes, of any style.
FAQ
Do I need to open the window for the robot to clean outside?
Only to place it. Open, hold the robot to the outer face until suction engages, anchor the safety rope indoors, and it does the rest — this is how second-floor windows get cleaned without a ladder.
What about double or triple glazing?
Irrelevant to the robot — it only touches the outer surface. Glazing depth, gas fill and coatings inside the unit make no difference.
Curved glass?
No — suction robots need flat glass. Gentle architectural curves break the vacuum seal.
If most of your windows are in the ✅ list, the next question is the money one: are robot window cleaners worth it? — the honest maths, UK prices included.