Best robot vacuums: We name the most effective cleaners

The convenience robot vacuums provide come at a cost: As much as $1,400 at the high end, with many of the best models running no less than half that. To help you determine which ones are worth the expense, we tested models from some of the most popular brands in a real-world lab: my home, where the floors are punished daily by two kids, three cats, and a dog.

I tasked each one with vacuuming a 400-plus square-foot space that includes low-pile carpet, hardwood flooring, and linoleum that was regularly littered with food crumbs, pet hair, tracked-in dirt, stray cat litter, and other debris. To maintain the real-world environment, each model also had to contend with random floor clutter during several cleanings.

Be aware even the most premium robot vacuums are a supplement, not a substitute, for your stand-up vacuum. Despite manufacturer claims, most just don’t have the same suction power of an upright. Think of them as an easy way to maintain your floors in between deeper cleanings with your current vacuum.

Fundamentally, the robot vacuums in our guide all operate the same way: They autonomously maneuver around your home on a couple of wheels suctioning debris from your floors. Two to four brushes on the bottom—both rolling-style agitators and spinning side brushes—grab dirt from the floor and wall edges respectively, and guide it into the suction area or direct it straight to a small, filtered dustbin. When cleaning is complete, or their battery is running low, they return themselves to their charging dock. But just how they get the job done can differ across manufacturers and models.

Autonomy puts the “robot” in “robot vacuum.” Virtually all models include an “automatic” mode that requires you to do nothing more than press a button on a remote, in an app, or on the vacuum itself to clean a room. This is great for ad-hoc cleaning, but most models can also be programmed to clean on a schedule. The latter scenario is great if you want them to work when you’re not home, or to create a regular cleaning routine. Some higher-end models also integrate with smart speakers, such as the Amazon Echo and Google Home, which allows you to control them using voice commands.

Just as your stand-up vacuum can be adjusted to clean either carpet or hard flooring, so too can a robot vac. Most feature the ability to change suction and other cleaning functions to adapt to different floor surfaces, either automatically or with input from you. They may also have a spot mode for more concentrated cleaning on a small area (cleaning up a spill, for example), include options for single- and double-passes of a room, or offer an option to focus just on cleaning along wall edges and baseboards.

The allure of robot vacuums is their promise to complete their task with minimal management from you. In order to do that, they must be able to navigate a room’s unique layout, maneuver around furniture and other obstacles, and avoid hazards such as falling down stairs and getting tangled in electrical cords.

Robot vacuums “see” the world through a combination of sensors. Cliff sensors let it know when there is an increase in distance to the floor—e.g., stairs or a sunken living room—so it doesn’t tip over the edge. Other sensors tell it when it has bumped into an object, so it can change direction, or is near a wall, so it can follow it. Still other sensors help the robot vacuum track how far it has travelled. Depending on the manufacturer and model, a robot vac might also include sensors that determine the amount of dirt present so it can adjust its cleaning mode accordingly.

Manufacturers are increasingly including mapping capabilities in some of their robot vacuums. These models use an onboard camera or laser reflections to produce a 360-degree view of the room. This allows the robot vac to create a map of the space and locate itself within that map.

The advantage of mapping is the vacuum will know which areas it has already cleaned and which it hasn’t, to avoid going over the same spot unnecessarily. It also lets it know where to resume cleaning if it must stop and recharge midway through the task. This makes it ideal for larger rooms and—because it’s still something of a premium feature—larger budgets.

In an ideal world, you’d clear all your floors of clutter before using your robot vacuum. But we live in the real one and that’s not always possible or desirable. Knowing this, many robot vacuums include some way to block off areas you don’t want it venturing into, whether it’s a pet’s area, your kids’ room, or a cluster of device cords in the corner. Often it’s just a length of magnetic tape you stretch in front of or on a forbidden area that the vacuum’s sensors will detect and tell it to avoid. But some models employ virtual barriers, such as the ability to designate boundaries on a floor plan that signal the robot to steer clear.

The dimensions of a robot vacuum matter for a couple of reasons. First, they will determine how well it can get into tight spots, such as under your kitchen cabinets and low-clearance furniture (couches and recliners). If it’s too tall, it won’t be able reach into these spots, or worse, it will get in and get stuck until you physically free it. Second, the bigger the robot vacuum, the larger the dustbin.

Robot vacuums don’t use expandable bags like many of their stand-up brethren do, so when it comes to debris capacity, what you see is what you get. There is no sweet spot for robot vacuum dimensions that we could determine—it really depends on your particular room layout—but a diameter of 13 to 14 inches and a height of 3.5 to 4 inches are the most common measurements we encountered.

Wi-Fi-enabled robot vacuums allow you to control them with a smartphone app instead of, or in addition to, a physical remote. That convenience alone doesn’t really warrant the extra cost these models command, but some model’s apps also provide other perks, such as detailed cleaning histories and the ability to save and edit floor maps for better navigation. Those models are worth considering if you’re cleaning large, intricate spaces.

While robot vacuums take over most of the cleaning, they have historically required the user to step in and manually empty the dustbin. Given that most robot vacuums’ have a very small dustbin capacity, they might need to be emptied multiple times per cleaning job, particularly if you have children or pets or live in a large home. That’s not just annoying, it can be downright uncomfortable if you have allergies or dust sensitivity.

Auto-emptying robot vacuums bridge the last mile of the vacuuming process with a charging dock that includes a canister vacuum and a dust bag that can hold one to two months of debris. When the robot docks after a cleaning job, its bin’s contents are automatically sucked into the dust bag. Typically, the robot’s companion app alerts you when the dust bag is full, at which point you will have to manually dispose of it. Many bags, however, seal themselves when you remove them, so no dust escapes.

Some robot vacuums include a mopping capability to meet all your floor’s cleaning needs with one device. While this sounds like a great idea, in practice it often yields subpar results. The problem is the method these hybrid devices use for wet cleaning. Mopping robot vacuums include a flat, small-capacity water tank that you fill from your tap. A microfiber cloth is then attached to the bottom of the tank, and the tank is installed under the robot. As the robot rolls across the floor, it drags the dampened cloth over it. This usually removes surface grime and spills but leaves deeper dirt and stains behind.

If you have a lot of hard flooring in your home, it’s worth considering a dedicated robot mop. These appliances are better suited to wet cleaning, spraying water directly on the floor to soften gunk and stains, and applying some agitation via a scrubbing pad or brush.

If you still want a vac/mop hybrid, look for one that has spinning brushes or pads as opposed to a cloth that attaches to the bottom of the appliance. A model with a docking station that can clean those brushes or pads and reservoirs for clean and dirty water are even better. Those models will, of course, cost quite a bit more.