Vacuum Wise

Robot vacuums: suction, mapping, and what the dock does

A robot vacuum is a low, round vacuum that drives itself. Its specification sheet has three parts — how it cleans, how it navigates, and what its dock does for you — and the third has become the one that decides the price.

What the category is

A round, battery-powered vacuum a few inches tall that maps a floor and cleans it on a schedule, returning to a dock to charge. Many now carry a mop pad as well, and the more expensive docks empty the bin, wash and dry the pads, and refill the water tank, so that weeks pass without the owner touching it. The cleaning itself is modest by upright standards; what you are buying is that it happens every day.

How to read the spec sheet

Suction is quoted in pascals, and the numbers have inflated from 2,000 Pa to 20,000 Pa in a few years without the robots becoming ten times better. Pa measures the vacuum at the intake with the inlet sealed, not what reaches the carpet through a brush and a gap. Compare it between robots and only between robots, and give more weight to the brush design and whether the listing names carpet boost.

Navigation is the specification that decides whether the robot finishes the room. LiDAR (a spinning laser turret on top) maps in the dark and produces the cleanest room maps; camera-based systems need light and vary more; the cheapest robots have neither and bounce off things, which works in one small room and nowhere else. Obstacle avoidance — usually a front camera or structured light — is what keeps it off cables and pet accidents, and the sheet should name it.

Mopping: a damp pad dragged behind the robot is not the same as a pad that vibrates or spins with pressure, and neither lifts the pad over carpet unless the sheet says so. A robot that cannot lift its mop will wet your rugs.

The dock: self-emptying holds weeks of dust in a bag; pad washing and drying keeps the mop from going sour; auto-refill tops up the clean water. Each adds cost and a footprint. The bag in a self-empty dock is a consumable the listing rarely prices.

Run time and bin size matter less than on other vacuums, because the robot recharges and resumes, but a 0.3-litre bin on a robot without a self-empty dock is a bin you empty daily.

Height is the figure people forget: a 10 cm robot fits under most sofas and a 12 cm one does not, and a LiDAR turret adds a centimetre.

Who it suits

Anyone who wants floors maintained rather than cleaned: a daily pass over open floors in a home without too many cables, thresholds or shag rugs. A self-emptying dock suits pet owners for whom the small bin is otherwise the whole chore.

Who should skip it

Anyone with mostly carpet and a house that gets properly dirty, stairs, or a floor plan with a lot of chair legs. A robot will not deep clean carpet, and it does not do stairs at all; an upright or a stick vacuum is still needed alongside it.

Where to start

Six of the 29 robot vacuums reviewed on this site, one per model, across manufacturers. Every review is written from the manufacturer’s published specifications — how, and what that leaves out.

All 29 robot vacuum reviews

Newest first. Consumables, accessories and parts that were once filed here are excluded.