Pascal (Pa)

Pascal, written Pa, measures pressure. On a robot vacuum box it tells you how hard the machine can suck air through its nozzle. Numbers like 10,000 Pa and 31,000 Pa are common.

The catch is that suction is only part of the job. Brush design, how firmly the robot presses down, and how slowly it drives all matter too. A 31,000 Pa machine can still leave dog fur in a thick rug, as one tester found.

Treat the Pa figure the way you treat horsepower on a car. Useful for comparing, useless on its own.