Roborock states 36,000 Pa of suction for the Saros 20 Flow. Dreame put 30,000 Pa on the Cyber10 Ultra at IFA, a figure reported from the show floor by Vacuum Wars. A couple of years ago the same shelf was advertising eight thousand. If the robot parked under your couch is rated at a fraction of those figures, the question worth asking is whether the gap means anything on your floor.
Mostly it does not, and the reason sits in what the unit measures.
What a pascal measures
A pascal is a unit of pressure: force spread over an area. On a robot vacuum spec sheet it describes how hard the motor can pull with the inlet blocked — a sealed, static reading, with no air moving through the machine. It is the ceiling of what the motor can do, taken in the one condition the robot is never in while it is cleaning.
When the robot is actually working, the inlet is open, air is moving, and the pressure that reaches the floor is whatever the rest of the system allows: the brush, the width of the opening, how well the machine seals against a hard floor or sinks into a rug, how full the bin is. Ecovacs — a company that sells robot vacuums and has every reason to like a big number — puts it in writing on its own site: a higher Pa rating "does not automatically mean better cleaning on its own", and can be "misleading on its own". It names airflow as the missing half. Pressure with no air moving does not carry debris anywhere.
Nobody certifies the number
There is a published international method for measuring how well one of these machines cleans. IEC 62929:2014 specified the essential performance characteristics of household dry cleaning robots and the methods for measuring them; IEC withdrew it on October 28, 2020 and replaced it with IEC/ASTM 62885-7:2020. What those methods produce is dust removal and coverage: how much of the test debris comes off the floor, and how much of the room the machine reaches.
The pascal figure is not one of those results. It is a motor specification, and each company decides for itself how to take it. Roborock's own product page for the Saros 20 Flow gives 36,000 Pa and not the conditions behind it, which is normal for the category rather than a Roborock quirk. So a figure from one brand and a figure from another were not measured against each other, and no third party is checking either one. Two numbers side by side are two marketing departments side by side.
Four things that decide it instead
- How the brush handles hair. With pets or long hair in the house, the difference between a good week and a bad one is whether you end up cutting a bundle off the roller with scissors. Roborock's answer is a dual anti-tangle system; Dyson's R1 splits the work between bristles for larger debris and the motor for fine dust. That mechanism deserves more of your attention than the headline figure.
- How wide it cleans. A full-width roller covers a room in fewer passes than a narrow opening with side brushes flicking debris toward it. Coverage per pass is a design decision, and it is not printed next to the pascals.
- What happens to the mop. In NIQ's 2026 home appliances outlook, mopping was the reason 46 percent of the robot vacuum buyers surveyed gave for picking their machine, against 12 percent who named AI. A pad that spreads yesterday's dirt around is the complaint people actually have; whether the dock washes it in hot water and dries it afterwards is the part that changes your week.
- Whether it reaches the dirt at all. A robot that cannot get under the couch has no suction under the couch, at any figure. Navigation, obstacle handling and how the machine crosses a threshold decide where that motor ever gets used.
When the number does mean something
Two cases, and they are narrow. Inside one brand's own line, the same company measured both models the same way, so a bigger number probably is a bigger motor — a legitimate comparison as long as you do not carry it across to another brand. And on deep-pile carpet pressure genuinely does matter, because the debris is down in the fibres and has to be pulled up through them. If your floors are mostly rugs, the thing to look for is whether the robot detects carpet and raises power for it, not the peak it can hit with the inlet plugged.
If you already own a robot
On hard floors, moving from a mid-range machine to the current top of the spec sheet is a change you will struggle to see. The things people do notice — hair wound around the roller, a mop that comes back dirty, a robot stuck on the same chair leg every Tuesday — are none of them pascals. For most people with a robot that still works, a new headline number changes nothing at all.
The honest version of the shopping advice is unglamorous: ignore the biggest type on the box, read what the machine does with hair, water and furniture, and accept that nobody publishes a number for any of it.
The number is easy to print and hard to feel, which is exactly why it leads every announcement. If what keeps your robot from cleaning is where it cannot go rather than what it cannot lift, the robot with legs is the more interesting direction this year. And if you are weighing a whole lineup rather than one spec, what Dyson put out this fall lays out the same trade-offs across several machines.
Last updated September 21, 2026