Pa is pascals, a pressure measurement taken at the motor — not down at your floor. There’s no standard test, so every brand measures it their own way, and the number on the box is the peak, not what it runs at day to day.

Where the number stopped meaning much

The jump from 2,000 to 10,000 Pa was real and you could feel it on carpet. The jump from 20,000 to 30,000 is marketing. Once a robot is picking up nearly everything on a surface, adding pressure gets you a couple of percentage points at the cost of battery life, noise, and faster wear on the roller.

It’s also worth knowing that Pa is self-reported. Brands have climbed from about 2,000 to well over 20,000 in a few years without cleaning performance improving anywhere near proportionally. When two robots list numbers that are close, the difference between them is inside the margin of how they each chose to test.

What actually determines pickup

Brush design comes first. The roller loosens debris and hair so the airflow can carry it away; suction alone barely moves anything embedded in a fiber.

How well the robot seals against the floor comes second. Suction generated at the motor is only useful if it reaches the floor, and air leaking around a poorly sealed intake wastes most of it.

A clean filter comes third, and it’s the one you control. A clogged filter restricts airflow more than any spec difference between two comparable robots. The most common “my robot stopped picking up” complaint I get is a filter nobody has tapped out in six months.

Dad’s Take

Suction is a real spec that got turned into a marketing race. Read the brush design, not the pascal number.