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How does a Roomba work?

How do Roomba vacuums work?

A Roomba is an autonomous robotic vacuum, which in simpler terms means it cleans the floor by itself and usually doesn’t need intervention from the user. 

Roombas were introduced in 2002 and since then have advanced to the point that they use the same technology as autonomous cars, can identify restricted areas in your home and can even charge their batteries by themselves. Due to the increasing technological advances of Roombas, buying one can be complicated and confusing. 

Read on for more information on how a Roomba works, its key components and how to choose the best one for your home.

Roomba features

Roombas are robot vacuum cleaners in the shape of a frisbee or large disc. The bottom of a regular Roomba has rotating brushes as any other vacuum. To function and move autonomously, Roomba’s first versions used sensors to avoid hitting walls or obstacles. However, this system can be inefficient because the vacuum randomly moves around your house and can pass more than once through the same area. As such, things have changed in recent years.

The newest versions of Roombas come with either Lidar (light detection and ranging) and Vslam (visual simultaneous localization and mapping). Both systems allow the Roomba to create a map of the space (your bedroom, living room, kitchen, etc.) to move around it systematically. This improves the efficiency of the vacuum while also allowing it to identify objects and areas that may need to be avoided.

Another key feature implemented in recent years is the clean and charging base, which serves as a station for your Roomba to empty itself and, if needed, to charge itself when not in use. 

Lidar vs. Vslam

Aside from the suction power, in the case of Roombas, the localization and mapping systems are crucial. After all, the added value of autonomous robotic vacuums relies on their ability to move independently through any space.

Lidar works with an invisible laser that spins on the top of the Roomba and collects information about the space. Vslam works with a small camera that points towards the ceiling.

Both systems are a significant improvement from previous sensors, but among users, some prefer Lidar to Vslam and vice versa. Lidar seems to have a faster and more accurate perception of the space. Since the laser is located and aimed closer to the ground, Lidar vacs tend to map the space better than Vslam models.

Vslam has less accurate depictions of space, which is of importance when you’re dealing with small spaces and no-go areas (areas that the Roomba must avoid). 

While Lidar may seem like the better option, this may change in years to come. Camera-based systems gather more information and as companies equip vacuums with more advanced processors, Roombas will likely feature better performance in the near future.

Clean and charging base

Recent versions of the Roomba come with a key feature: a self-cleaning and charging dock. If used properly, your vacuum can work on its own. You’ll have to check it once every couple of months, but over time, it gets closer to a real autonomous machine as it learns your home. 

Models that include a clean base have a higher price by 30-40%, so it’s something to consider before buying one.

App control and keep out zones

Nowadays, almost every model of autonomous vacuums comes with an app. The app lets you activate and deactivate the vacuum and have complete control of the spaces identified by it. The app also lets you set “keep out zones,” which are areas in your home that the Roomba doesn’t have to vacuum. 

Best Roomba vacuum cleaners

iRobot Roomba i7+

One of the best robot vacuum cleaners on the market. As with all high-end iRobot versions, the Roomba i7+ functions with Vslam. This model has everything you can expect from a quality Roomba: clean base, a user-friendly app, keep out zones, WiFi and much more. 

Sold by: Amazon, Bed Bath & Beyond, Best Buy and Home Depot

iRobot Roomba i3

This affordable model of Roomba has some of the features of the Roomba i7+, but without the clean base and Vslam. The Roomba i3 still functions with floor tracker sensors. Its moderate price makes up for some of its shortcomings. 

Sold by: Amazon, Bed Bath & Beyond and Best Buy

iRobot Roomba s9+

It calls itself “the greatest automatic vacuum cleaner ever created.” This may sound exaggerated, but it truly has quality features, and it has some of the highest suction power among robot vacs. If budget isn’t a concern, this is a fantastic choice. 

Sold by: Amazon, Best Buy and Home Depot

Best Roomba vacuum alternatives


Ecovacs Deebot T8 AIVI

This is a highly advanced robot vacuum cleaner. Aside from using a Lidar system, Ecovacs Deebot also uses a frontal camera, which allows the vacuum to identify objects. 

Sold by: Amazon and Best Buy

Shark IQ Robot Vacuum AV1010AE

Has all the qualities of a high-end robot vacuum but at a lower cost. Substantial suction power, Vslam system and a cleaning base that holds up to 30 days of dirt. 

Sold by: Amazon 

Neabot NoMo

Another solid option if you’re looking for a truly smart robot vacuum cleaner. The Neabot NoMo has the combination of Lidar to navigate and Vslam to identify objects. In terms of vacuums with a clean base, it’s also affordable. 

Sold by: Wayfair


Roborock S4 Max Robot Vacuum

If you’re on a budget but still want a decent automatic vacuum cleaner, this is a mid-range option. It has the precision of a Lidar system, keep-out zones configuration and high suction power. 

Sold by: Amazon


Juan Sebastián Torres is a writer for BestReviews. BestReviews is a product review company with a singular mission: to help simplify your purchasing decisions and save you time and money.

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