How to choose a robot vacuum: the specifications that actually matter

Robot vacuum listings are full of numbers and feature names. Some of them genuinely help you decide. Others are hard to compare. This guide goes through the main areas, starting with the one that matters most: your own home.

Start with your home, not the spec sheet

Before comparing models, write down a few facts about where the robot will work. They will tell you which features are worth caring about.

• Floor types. Mostly hard floors, mostly carpet, or a mix with rugs?
• Pets and hair. Manufacturers market brush designs aimed at reducing hair wrapping, so brush design and how easy the brush is to remove and clean may matter to you.
• Size and layout. A small flat and a multi-room house put different demands on battery, mapping and navigation.
• Thresholds, furniture and clutter. Low sofas, door strips, cables and shoes all affect what a robot can do.
• Upkeep you are willing to do. Emptying a bin, rinsing pads and replacing parts are ongoing jobs.

Navigation and mapping

Navigation describes how a robot works out where it is and where to go. Broadly, you will see these approaches:

• Basic navigation. Simpler models tend to move around without a map, bumping into obstacles until the job is done.
• Camera-based mapping. Cameras pick out features such as corners and furniture edges to estimate the robot's position and build a map.
• Laser-based mapping (often called LiDAR). A sensor sends out laser pulses and times their return to measure distances and build a map.

Maps are what make features such as route planning and, in some apps, no-go areas possible. The sources we checked say camera-based mapping depends on decent lighting and works less well in dim rooms, while laser-based mapping does not rely on ambient light. Those descriptions come from a manufacturer and an independent site, and we have not tested either approach. If a robot will often run in a dim room, check what the manufacturer says about low-light operation.

On many models the laser sensor sits on top of the robot, so check the stated height against the gap under your furniture. How well any individual robot navigates your home is something these specifications cannot tell you.

Suction figures

Listings quote suction in different ways. Some manufacturers use pascals (Pa), which measures vacuum pressure. Others quote watts, which also takes airflow into account. One news report on Korean consumer testing and standards made the point that pressure alone does not describe suction, and that there is no clear international standard for robot vacuum suction. That is a single report from one country, and we have not verified how each manufacturer arrives at its figure.

• Do not assume a bigger number from one brand is stronger than a smaller number from another.
• Some robots offer several power levels, including boost modes, so check which mode a quoted figure refers to.
• In our view, suction is only one part of cleaning performance. Brush design, carpet handling and route planning may also matter, and independent test results would be needed to know how they combine.

Our approach: BuyMetric will not rank different brands on suction figures alone.

Brushes and carpet handling

Manufacturers describe different brush designs (for example rubber, bristle or combination brushes) and make claims about reducing hair tangling. These are manufacturer claims, and whether a design works as described is something independent testing would need to show. If you have carpets or deep rugs, check whether the robot detects carpet and what it does, and what maximum carpet height is stated.

Mopping

Many robots include a water tank and mop cloth or pads. Mopping adds components and upkeep, and designs differ. We cover this in our guide to robot vacuum versus robot vacuum and mop.

Docks

The dock is where a robot charges, and on some models it does more. Typical levels are:

• Charging dock only. The robot recharges; you empty its dust bin yourself.
• Self-emptying dock. The dock removes dust from the robot into a bag or similar container. One independent buying guide says this adds cost, takes up space and is often loud, and that replacement bags are an ongoing expense. Check what the bags cost and how long one is stated to last.
• Docks for mopping models. Depending on the model, a dock may refill the water tank, wash the mop pads and dry them with warm air. Check which of these, if any, a given dock does.

Check dock dimensions and the clearance needed around them against the space you have. If noise matters to you, look for what the listing or independent reviewers say about emptying noise, and whether emptying can be scheduled or adjusted.

Battery and runtime

Listings usually give battery capacity in milliamp-hours (mAh) and a runtime in minutes. Runtime depends on the mode. Manufacturers' own guidance says that higher suction uses more power, so quiet and standard modes run longer than turbo or maximum modes, and that carpet can trigger suction boosts. When you see a runtime figure, check which mode it refers to. Independent testers measure runtime themselves (one consumer organisation runs each robot from full charge until its motor stops), which is a reminder that a listed runtime is a manufacturer claim.

Some robots return to the dock when the battery runs low, recharge, and then continue cleaning; manufacturer pages describe this for specific models. If a model you are considering does this, check how long recharging takes. One manufacturer lists charge times that differ by model and notes they can vary from run to run. In our view, for a larger home this feature may matter as much as a single runtime figure.

Obstacle avoidance

Basic robots find obstacles by bumping into them. Some models add sensors, and some use cameras with AI-based object recognition. One independent buying guide mentions pet bowls and pet mess as examples that manufacturers target. This is manufacturer-stated capability. The sources we checked do not tell us how reliably these systems work in practice, so read detection claims as claims: look for which objects are listed and any minimum size, and look for independent testing of the specific model.

Cameras also raise privacy questions. See the next section.

Size, height and climbing

Measure before you buy. Three numbers matter:

• Robot height, against the gap under your furniture.
• Stated threshold or climbing height, where a listing gives one, against the door strips and rug edges in your home.
• Dock footprint, against the space where you will place it.

App, smart-home features and privacy

One independent buying guide says pricier models typically add Wi-Fi, app control, scheduling and voice-assistant support, while some cheaper models use buttons or a remote and have no connectivity. A consumer-organisation article from Australia reports that robot vacuums may create maps of your home, that some brands send maps or camera images to cloud servers in some circumstances, and that companion apps may collect account and location data. Its advice includes reading the privacy policy, thinking carefully before agreeing to data sharing and looking for no-go areas. Practices differ between brands and markets.

When you compare models, check which features need an account or internet connection, and whether the manufacturer states how long it will provide software updates. Treat a missing statement as unknown.

Noise

Some listings quote noise in decibels (dB) for a stated mode. Check which mode. The sources we checked do not establish a common way of measuring noise, so avoid precise comparisons between brands, and consider dock emptying noise separately.

Upkeep and running costs

Check which parts the manufacturer lists as replaceable (for example brushes, filters, mop pads and dock bags), whether they are sold, and what they cost. Independent and retailer guides we checked identify dock bags as an ongoing cost, note that on some models you replace and clean mop pads yourself, and say brushes, filters and water tanks need periodic attention. A low purchase price can be offset by the cost of consumables, so we cover this further in what makes a robot vacuum good value.

Guarantee and your rights

Check the length and scope of the manufacturer's guarantee and the retailer's returns terms. You may also have statutory consumer rights when you buy goods in the UK; Citizens Advice explains them. This is general information, not legal advice.

A short buying checklist

• I have noted my floor types, pets, layout and clutter.
• I have measured under-furniture clearance, thresholds and dock space.
• I know which navigation and app features I will actually use.
• I have treated suction, runtime, noise and obstacle-avoidance figures as manufacturer claims, and checked which mode each refers to.
• I have checked which parts need replacing, and what they cost.
• I have checked the privacy policy, especially for models with cameras or cloud features.
• I have checked the retailer's return terms and the manufacturer's guarantee.
• I have compared the price at more than one retailer, and over time if I can.

What BuyMetric will add

We plan to record manufacturer specifications with their sources, track prices over time, and publish value comparisons with criteria stated in advance. None of that is live yet. When it is, it will be labelled as described in our methodology. For now, see the robot vacuums overview or the next guide on vacuum versus mop.

Evidence notes

We checked the main technical statements in this guide on 7 October 2026 against the sources below. They are a mix of manufacturer and independent publications, and they are general background, not tests of any product. Manufacturer sources describe their own technology and products. Where the sources did not support a statement, we have worded it as something to check.

• Navigation types and lighting: Ecovacs UK blog (manufacturer) and Mighty Gadget (independent). Both describe camera-based mapping as less effective in dim light. The Ecovacs piece says laser sensors are generally placed on top of the robot.
• Basic navigation, docks and bags, connectivity, obstacle avoidance: TechRadar buying guide (independent).
• Suction units and standards: Korea JoongAng Daily (news report, Korean context).
• Battery modes and recharge-and-resume: Eufy battery guide and iRobot support article (both manufacturers). For how runtime is tested independently: Consumer NZ test method.
• Privacy and data: CHOICE (independent consumer organisation, Australia).
• Not established by the sources we checked (so worded cautiously): how reliably any obstacle-avoidance or anti-tangle design works; how suction figures relate to real-world cleaning; how noise figures are measured; how long manufacturers support their software.