Robot vacuum suction in Pa explained

What a pascal figure measures

A pascal is a unit of pressure. On a vacuum cleaner, the Pa figure normally describes the maximum pressure difference the fan can create between the outside air and the inside of the vacuum, usually measured with the inlet blocked. It is sometimes called sealed suction.

That tells you how hard the fan can pull, but not how much air moves through the brush when the robot is cleaning. A robot with a very high sealed figure but a narrow air path may not pick up more than one with a lower figure and better airflow. There is also no single agreed test method across brands, so figures from different makers are not strictly comparable.

Airflow, brushes and sealing

In real cleaning, three other things matter as much as Pa. Airflow, the volume of air moving through the robot, is what carries dust and hair into the bin; the Ecovacs X12 OmniCyclone listing, for example, quotes 22 litres per second alongside its 22,000 Pa. The brush lifts dirt out of carpet and sweeps it to the inlet. And the seal between the brush housing and the floor decides how much of the fan's pull reaches the dirt.

That is why a robot with a good rubber brush and tight seal can beat a higher-Pa robot with a worn brush on carpet. On hard floors, almost any modern robot has enough suction for dust and crumbs.

Typical figures in current listings

These come from Amazon UK listings for robots in our guides. They show how widely figures vary, not a ranking.

Robots for carpet →

How much suction do you need?

For mostly hard floors, a robot in the 4,000 to 8,000 Pa range with a good brush is usually plenty. For carpets, pets and long hair, a higher figure helps, particularly with carpet boost, but brush design and anti-tangle features matter at least as much.

Higher suction also uses more battery and makes more noise, so most people run their robot on a standard setting and let carpet boost raise power only where needed. Our guides to battery life and carpet and rugs explain the trade-offs.

Comparing Shark and iRobot

Shark tends to describe suction against other models or competitors, and iRobot as a multiple of its older 600 series, for example 70 times or 175 times more suction. These claims cannot be converted to Pa, so you cannot compare them directly with a Dreame or Ecovacs figure.

Instead, compare these robots on brush design, self-emptying, navigation and carpet features. Our Shark against Roomba comparison and Shark robot range do just that.

Suction levels in the app

Most apps offer three to five suction levels, often named quiet, standard, strong and max. The headline Pa figure applies only to the top level. Day to day, standard is enough for hard floors and light carpet, and carpet boost raises power automatically when the robot drives onto a rug.

Use max for a monthly deep clean of carpets, or in a pet's favourite room, rather than every run. Running on max all the time shortens runtime, raises noise and wears the battery faster, often for little visible gain. Many apps let you set suction per room, which is the best way to put extra power only where it helps, such as the hallway and living room carpet.

Frequently asked questions

What robot vacuum has the strongest suction? On current UK listings, some Ecovacs and Dreame flagships quote 25,000 to 30,000 Pa. Highest quoted suction does not guarantee the best pick-up.

Is 10,000 Pa enough? For most homes, yes. Beyond that, brushes, airflow and carpet features usually matter more.

Why has my robot lost suction? Usually a full bin, clogged filter or blocked inlet. See robot vacuum losing suction.

Does higher suction drain the battery faster? Yes. Max power can shorten runtime considerably compared with a standard setting.