Narwal Freo Z10 Pro

Suction in pascal, as the maker measures it. More pascal helps on carpet, but it says little about how well the robot picks grit off a hard floor.

A brush that guides hair to the side instead of letting it wind around the shaft. It saves the cutting work in homes with long hair or pets.

The side brush swings out in a corner or along a kickboard, so the dust there is swept in too.

The robot notices when it drives onto a carpet. Most then raise their suction, and a mopping robot lifts its mop or leaves it at the dock.

Whether the robot copes with pet hair: a brush that hair does not wind around and a dock that empties the bin for you. Where the maker does not say so itself, we read it from those two.

How the mop is built: flat pads, two spinning discs or a roller. Discs press harder on dried-on dirt, a roller rinses itself while it works.

How far the robot lifts the mop when it drives onto a carpet. From about 10 mm a medium pile stays dry.

The pad slides out along a wall or a kickboard, so the last few centimetres are mopped as well.

The dock empties the robot’s dust bin, usually after every run. You only empty the dock’s bag or bin.

The dock collects dust in a bin instead of a disposable bag. No bags to buy, but you empty it yourself.

How much the dust bag in the dock holds.

How long the maker says a dust bag lasts with daily use. With pets or a lot of carpet it is shorter.

The dock washes the mop for you, so you do not rinse it by hand.

How hot the dock washes the mop. Above 60 °C grease comes off, which is what keeps a mop from smelling.

The dock dries the mop afterwards, so it does not sit there wet and start to smell.

Drying is done with warm air instead of cold. It is faster and it helps against smell.

The dock mixes detergent into the water itself, from its own bottle.

The clean water tank in the dock, which wets the mop.

The tank that catches the dirty water from the mop. You empty this one yourself.

The width, depth and height of the dock. Measure the spot you have in mind, and leave room for the lid and for the robot driving in.

How the robot maps your home and follows that map. Lidar measures with a laser and works in the dark, a camera looks along and recognises more.

How the robot sees loose things on the floor, such as cables, socks or a pet accident. A camera with depth sensing sees more than a bumper that reacts on contact.

The highest threshold the robot takes, as the maker states it. Measure your own: the step into a bathroom or onto a balcony is often higher.

An extending leg or wheel that carries the robot over a high threshold. Without one it usually stops at about 2 cm.

The noise in decibels, in the setting its source names: makers mostly give the standard setting, shops often the highest. 65 dB is like a vacuum at half power, 55 dB like a conversation.

Which voice assistants the robot works with, such as Google Assistant or Alexa.

Which Wi-Fi the robot connects to. Many robots only use 2.4 GHz, so check that your router still broadcasts it.