Roborock Saros 20 Robot Vacuum

Summary

We kept raising the threshold height, one strip at a time, until the robot started stalling halfway, and that’s where the most interesting detail of the Saros 20 showed up. Roborock says it climbs up to 8.8 cm (3.46 in on the Amazon.co.uk listing), and that’s true, but not in a single step: on a single step it always cleared up to 4.3 cm and began to fail at 4.6, whereas on a two-step threshold adding up to 8.6 cm it got across all three times we tried.

The rest follows the same pattern of a robot that does things well and talks about them in big numbers. It picked up an average of 98.0% of the dirt across hard floor and rug, the highest figure we’ve measured in this comparison, with a split brush that finished the rug test with just one long hair caught and no clumps.

The 36,000 Pa it quotes is the biggest number in the category right now, although we’ve measured enough robots to know that pascals alone don’t decide a ranking. What you do notice is that suction combined with a brush that doesn’t tangle, which is what keeps performance up after months of use in a home with pets.

At 7.98 cm tall it slips under low sofas and beds where most premium robots can’t go, because it does without the rotating turret and handles navigation with a laser and a camera. If you have low furniture, that measurement matters more than anything else on the spec sheet.

Where it falls a little short is mopping light-coloured floors. All four stains go in two passes, but the tomato on laminate leaves a shadow you can see against the light, so in a home with light laminate expect to go over that particular stain yourself.

Analysis and verdict

Suction power – Score: 8.9/10

With a single pass on maximum it left 0.2 g of the 30 g we spread on hard floor, practically nothing. On the short-pile rug 1.0 g remained, which is also the best result of all the robots that have been through this circuit, and what survives is fine flour sunk between the fibres, not loose rice on top.

The main brush is split into two halves combining rubber and bristles, and that detail is what keeps the result up over time. When we checked it after the rug, we found one long hair caught at one end, with no clump formed and no need for scissors, which is exactly the kind of maintenance that becomes tiresome with classic bristle brushes.

What we didn’t see was the chassis lifting. On the short rug in our test it kept its normal height and raised its suction, with no noticeable lift. The system is designed for medium and long pile, so if your rugs are thin you won’t notice that feature, however prominently it appears in the brochure.

Battery life – Score: 9.2/10

It quotes up to 240 minutes from a 6,400 mAh battery, a lab figure in gentle modes that looks nothing like a clean with rugs along the way. It completed our living room, hallway and bedroom circuit in 72 minutes on medium, without even considering a top-up charge.

The figure that matters is what came after: it docked with 58% battery left, the biggest margin of all the robots we’ve measured on this route. With that reserve you can do another floor or repeat the busiest area without the robot having to stop, charge and resume, which is what turns a clean into a whole afternoon.

Consumption rises on the rugs, because that’s where the suction ramps up, but it never put the route at risk. In a two-bedroom flat you’ll have margin to spare, so it’s an advantage that only really pays off above a certain home size.

Mopping – Score: 8.6/10

The two spinning mop pads press against the floor with adjustable pressure and are washed in hot water at the station, and you notice it with dried tomato, the most stubborn stain. It went in two passes on all four combinations we tested, although on laminate it left a faint shadow that’s only visible against the light.

Edges are its strongest point. The side arm pushes the mop out towards the wall and left us a strip of just 0.2 cm unmopped, one of the lowest figures we’ve measured. The manufacturer’s claims need some nuance, though: reaching zero is a lab result, and against a real wall, with its skirting board and irregularities, a couple of millimetres remain.

With rugs it does what it should. It detects them, lifts the mop pads and crosses them without leaving any dampness you can feel on short pile. What stops it scoring higher is that film on the laminate, which puts it behind the robots that cleared all four stains without a trace.

How it handles thresholds and level changes

This is the feature that sets it apart, and also the one least well explained on its spec sheet. On a single step it cleared 4.3 cm in all three attempts, failed one in three at 4.5 and only got over once in three at 4.6. The 8.8 cm it advertises refers to something else, a stepped threshold with two levels in a row, and there it crossed all three times with 8.6 cm in total.

In a real home, that means it handles the steps between rooms, raised floors and patio door sills on its own, which is where most robots give up. What it won’t do is climb a stair, even though its height falls within the brochure figure.

The station and the app

The dock empties the bin, washes the mop pads in hot water and dries them, so weekly maintenance comes down to checking the tanks. On the other hand it takes up a fair bit of space and the emptying cycle is clearly louder than the robot cleaning, so think about where you’ll put it before anything else. The app, meanwhile, offers so many strategies for rugs, mop pads and obstacles that your first evening goes on setting it up to your liking.

Pros

• 98.0% average pick-up across hard floor and rug, the highest we’ve measured, so you can skip the touch-ups with a handheld vacuum.
• Crosses stepped thresholds of up to 8.6 cm in total, so the steps between rooms and raised floors are no longer a barrier for the robot.
• Returns to the dock with 58% battery after a three-room circuit, enough margin to do another area without stopping to recharge.
• 7.98 cm tall because it does without the rotating turret, so it fits under low sofas and beds where other robots in its class can’t.

Cons

• Leaves a shadow of dried tomato on laminate, visible against the light after two passes, so on light floors you’ll have to go over that stain by hand.
• 1.0 g of fine flour stays in the rug and the chassis doesn’t lift on short pile, because the lift is designed for medium and long pile and doesn’t kick in on thin rugs.

Our test

Test 1: Suction power – 30 grams of rice and flour on hard floor and rug

We tested the Saros 20 in Spain, and it’s the same model sold on Amazon.co.uk. We spread 30 g of a rice and flour mix over a 50 x 50 cm square and let it make a single pass on maximum, first on hard floor and then on a short-pile rug. We collected what was left with a handheld vacuum and weighed it on scales, the same set-up we’ve used to measure every other robot in this comparison.

0.2 g remained on hard floor and 1.0 g on the rug, and when we checked the brush roll we found two or three loose hairs with no clump. If what you mostly vacuum is crumbs, grit and hair, you won’t even see that flour residue; if you have rugs and someone with a dust allergy at home, plan on scheduling a second pass over them. We can’t say how the brush copes with very long hair built up over months.

Test 2: Battery life – a timed three-room circuit from dock to dock

We had it clean a living room, hallway and bedroom circuit with two rugs along the way, on medium, timing it from leaving the station until it docked again and noting whether it needed to recharge. It’s the same route every other robot in the ranking has done, so we can compare times between them rather than against the manufacturer’s spec sheet.

It took 72 minutes and docked with 58% battery, without a top-up charge. Consumption rises on the rugs and during avoidance manoeuvres, although it never put the route at risk. That margin is what lets a large home get cleaned in one go; in two rooms you’ll have half of it to spare and you’ll be paying for battery life you don’t use.

Test 3: Mopping – dried milky coffee and tomato on laminate and porcelain tiles

We left a milky coffee stain and a tomato sauce stain to dry for 30 minutes on laminate and on porcelain tiles, and asked for two passes on medium flow. We checked for rings once dry, in normal light and against the light, measured the unmopped strip next to the skirting board with a ruler and watched what it did when it reached the rug.

Three of the four stains left no trace; the fourth, tomato on laminate, left a film you can only see against the light. Next to the wall, 0.2 cm was left uncovered, and on the rug it lifted the mop pads and crossed without leaving it damp to the touch. If you mop mixed floors every day it’s more than worth it; if your floor is light laminate and your dried stains tend to be sugary, plan on wiping with a cloth now and then.

If you want to know more about what to look for, take a look at our robot vacuum buying guide, with the best models we’ve tested to help you choose the right one for you.