Quick answer: A magnetic window cleaner (£15–£40) works on thin single glazing and cleans both sides at once — but modern double and triple glazing is usually too thick for the magnets to grip, and you're still doing all the scrubbing by hand. A robot window cleaner (£150–£300) works on any glass thickness, cleans automatically, but does one side at a time. For most UK and EU homes with double glazing, the magnet isn't a real option — the choice makes itself.
Two gadgets promise to end your window-cleaning misery. One costs about as much as a takeaway. The other costs as much as a decent pair of trainers. Naturally, you want to know if the takeaway-priced one is enough.
Here's the comparison nobody selling either product gives you straight.
How each one works — and the physics catch
Magnetic cleaner: two pads with strong magnets sandwich the pane, one inside, one outside. You move the inner pad by hand; the outer follows. Clever — you clean the unreachable outside face from indoors.
The catch is in the word sandwich. Magnetic force drops off sharply with distance. A Victorian sash with 4mm glass? Fine. A modern double-glazed unit — two panes plus a 12–20mm gas gap, easily 24–28mm thick? Most magnetic cleaners either can't grip at all or grip so weakly the outer pad slides down mid-clean and drops. (That's why they're sold in glass-thickness ratings, and why the reviews split between "brilliant!" and "fell off my window on day one." Both reviewers are right — they have different windows.)
Robot cleaner: a motorised unit holds itself to one face of the glass with vacuum suction — the CleanBot R1 pulls 6,500Pa — then drives itself across the pane in overlapping N/Z passes, spraying a fine mist and wiping as it goes. Glass thickness is irrelevant because it never needs to "reach through" the pane. Full mechanics here.
Head to head
| Magnetic cleaner | Robot cleaner | |
|---|---|---|
| Price | £15–£40 | £150–£300 (CleanBot R1: £173) |
| Double/triple glazing | ❌ Usually too thick | ✅ Any thickness |
| Effort | You scrub every stroke | Press start, walk away |
| Both sides at once | ✅ (its one big win) | ❌ One side per session |
| Corners & edges | Weak — pads are round, corners stay grubby | Edge-detection reaches frames |
| Streaks | Depends entirely on your technique | Consistent machine passes |
| Safety fail-safe | A string on the outer pad | Tether + backup battery + anti-drop layers |
| Big panes / patio doors | Exhausting | Where robots shine |
Where the magnet honestly wins
Let's be fair to the £20 gadget:
- Thin single glazing in older flats — it does the job, cheaply.
- Sealed windows where you truly cannot access the outside face and the glass is thin enough. This is the one scenario where a magnet does something a robot can't: clean a face no one can touch. (If your building has thick glazing, though, you're back to square one — our apartment window guide covers the alternatives.)
- Budget. If £20 is the budget, it's the best £20 option.
Where the robot wins
- Any modern home. Building regs have made double glazing near-universal in the UK and EU — which quietly disqualifies most magnetic cleaners before the race starts.
- Volume of glass. Ten panes with a magnet is an upper-body workout with wet sleeves. Ten panes with a robot is ten button presses.
- Consistency. The robot cleans pane #10 exactly as well as pane #1. Your arm does not.
- Anyone who shouldn't be leaning into window reveals — the magnet still needs you pressed against every pane, working the full area by hand.
The verdict
Check your glazing first. If you have modern double glazing — and in the UK/EU you almost certainly do — the magnetic cleaner isn't really in the running; the physics rules it out. If you have thin single glazing and one awkward sealed window, spend the £20.
For everything else, the honest framing isn't "cheap vs expensive" — it's manual gadget vs automatic machine. One still costs you your Saturday. The CleanBot R1 costs £173 once, carries a 24-month warranty, and does the scrubbing part of your life for you.
FAQ
Do magnetic window cleaners work on double glazing?
Usually not well. Double-glazed units are typically 24–28mm thick, and most magnetic cleaners are rated for much thinner glass. Weak grip causes the outer pad to slip or drop.
Can a robot window cleaner clean both sides of a window?
Not simultaneously — you run it on the inside face, then place it on the outside face where accessible (openable windows, balcony or patio glass).
Which is better for a flat: magnetic or robot window cleaner?
Check your glass. Thin single glazing: a magnetic cleaner is a cheap fix. Double glazing (most modern flats): a robot is the only one of the two that will physically work.
Are magnetic window cleaners safe?
Mostly — the outer pad has a safety cord — but weak grip on thick glass can drop the pad mid-clean, and you still do all the reaching and scrubbing yourself.
Got double glazing? Skip the magnet lottery — see the CleanBot R1 robot window cleaner, £173 with free UK delivery over £75.