Robot Vacuum Buying Guide: what really matters

Navigation: the factor that matters most

If you only get one thing right, make it this. A robot vacuum is only as good as its ability to cover the whole floor without missing patches, getting stuck, or eating your charging cables. There are broadly two approaches, and the gap between them is enormous.

Random or bump navigation is what you find on the cheapest robots. The machine drives in a roughly methodical pattern, changing direction when it hits something. It has no memory of the room, so it cleans by sheer persistence rather than logic. On a small, open hard floor it copes; in a larger or cluttered home it leaves missed strips, takes far longer, and you can never tell it to clean one room. The eufy RoboVac 11S Max is a good example — it bumps around sensibly and, for a small flat, that is genuinely enough.

LiDAR laser mapping is the upgrade that changes everything. A spinning laser turret builds an accurate floor plan, so the robot cleans in neat parallel lines, knows where it has been, and lets you send it to a single room from an app. It is the most worthwhile feature you can pay for, and it now appears at surprisingly low prices: the Roborock Q5 Pro has proper LiDAR mapping for under £300. Camera-based navigation (vSLAM), as on the iRobot Roomba Combo j7+, achieves the same room logic and adds genuinely clever obstacle avoidance that dodges cables and pet mess. The honest takeaway: a robot with high suction but poor navigation will still miss half your floor. Buy the brain first.

Suction and Pa: useful, but don't over-weight it

Suction is measured in pascals (Pa), and the headline figures range from around 2,000 Pa on budget models to roughly 6,000 Pa on flagships. More suction does help — chiefly on carpet, where embedded grit and pet hair hide below the surface and need real pull to lift. On hard floors, almost any robot here has enough suction; the brush sweeping debris toward the inlet matters as much as raw power.

The trap is treating Pa as a single score for quality. A 5,500 Pa robot that navigates randomly will still leave grit in the corners it never reaches, while a well-mapped machine with moderate suction cleans the whole floor properly. Pa is a tie-breaker between robots that navigate well, not a substitute for navigation. If your home is mostly carpet, lean toward the higher figures and a robot designed for soft flooring — the Shark Matrix Plus drives a tight grid pattern and makes repeated passes precisely because a single pass rarely lifts everything from a rug.

Mopping: only worth it for hard floors

Mopping is the feature most likely to disappoint if you buy it for the wrong home. A robot mop is excellent at the daily job of keeping sealed hard floors free of dust film, dried spills and paw prints. It is not a deep scrub of grouted tiles, and it will do nothing useful for a carpeted house. If your floors are mostly carpet, treat mopping as a non-feature and spend the money on suction and navigation instead.

If you do have hard floors, the quality of mopping varies widely. The cheapest systems drag a damp cloth, which wipes rather than cleans. Better robots use a vibrating pad — the Roborock Q5 Pro's light mop is this type — while the best use dual spinning pads that actually scrub, as on the Roborock S8 Pro Ultra and Dreame L10s Ultra. One detail is non-negotiable in a mixed-floor home: auto-lift. The mop pads must raise when the robot crosses onto carpet, otherwise it drags a wet cloth across your rugs. Every mopping robot worth buying for a typical British home does this; avoid any that does not.

The dock: manual, self-empty, or all-in-one

The dock decides how often you have to get involved, and there are three levels. A manual dock simply charges the robot; you empty the small onboard bin yourself, often every couple of cleans. There is nothing wrong with this for a small, low-dust home, and it keeps the price down.

A self-empty dock sucks the robot's bin into a large sealed bag in the base, typically lasting 30 to 60 days before you change it. The Roomba Combo j7+'s Clean Base is the classic example. This is the single biggest convenience upgrade for pet owners and allergy sufferers, because the dust goes straight into a sealed bag instead of puffing back at you.

An all-in-one self-cleaning dock goes further still: as well as emptying the bin it refills the water tank, then washes and hot-dries the mop pads so they never go mouldy. The S8 Pro Ultra and the more affordable Dreame L10s Ultra both do this. It is the closest a robot gets to hands-off for weeks at a time, but the docks are large and need real floor space, so measure before you commit.

Brushes, filters and maintenance

The parts that touch the floor decide how much fuss you live with. The main roller brush comes in two styles: traditional bristles, which lift carpet well but tangle badly with long hair, and rubber anti-tangle brushes, which let hair slide off rather than wrap. If anyone in the house has long hair or you own a pet, an anti-tangle brush saves you cutting hair off the roller every week — it is worth seeking out.

Beyond the roller, plan for routine upkeep. The side brush that flicks debris from edges wears and occasionally needs replacing. The filter should be tapped out regularly and swapped every few months; a HEPA-grade filter is worth having if allergies are a concern. Mopping robots need their water tanks rinsed and pads washed unless the dock does it. None of this is onerous, but a robot is a machine you maintain, not a magic box — factor a few pounds a year for consumables into your thinking.

Price tiers: what your money buys

Robot vacuums fall into three sensible tiers, and there is a clear sweet spot. At the budget end, around £150, you get strong-enough suction and a slim body but no mapping and no mop. For a small flat or as a daily top-up cleaner, the eufy RoboVac 11S Max is the rational buy and does not pretend to be more.

The value sweet spot sits at roughly £250 to £300, and it is where most people should shop. Here you finally get the two features that transform a robot — real LiDAR mapping and strong suction — without paying flagship money. The Roborock Q5 Pro is the standout: an accurate map, room-by-room control and 5,500 Pa of suction for under £300, with a self-empty dock available if you want it later.

The premium and all-in-one tier starts around £700 and climbs past £1,000. This is where the self-cleaning docks live, along with the best mopping and obstacle avoidance. The Dreame L10s Ultra brings the full self-cleaning dock for several hundred pounds less than the very top, while the Roborock S8 Pro Ultra is the most thorough hands-off cleaner here, at a price to match. The Roomba Combo j7+ sits in between as our best overall pick, prized less for raw numbers than for being the robot that copes best with a real, cluttered home.