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ZDNET’s key takeaways

• Your yard matters more than the robot mower’s brand.
• Navigation type can make or break a robot mower.
• Match the mower to your terrain, budget, and obstacles.

A robot lawn mower is quite an expensive purchase, and one that shouldn’t be made lightly. There are multiple factors to consider before you choose a robot mower, beyond the brand’s claims of keeping your yard trim and tidy. From your yard layout to the navigation type, robot lawn mowers are not created equal.

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I’ve been testing robot lawn mowers for about three years now, since they became widely popular. In that time, I’ve learned the ins and outs of how robot mowers operate, what sets them apart, and what you need to know before committing to a model.

How to choose the right robot lawn mower

Robot lawn mowers are designed and built for very specific purposes and circumstances, so it’s not a one-size-fits-all solution. I’ll go exactly what will help you determine if a specific model is right for your yard, so you can consider this a checklist.

It’s not about the mower, it’s about the yard

The TL;DR is the type of yard you have at home will determine the robot lawn mower you choose. 

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Don’t marry a brand or model simply because you’ve heard good things about it — make sure it’s a good fit for your circumstances first. You can choose the right robot lawn mower for your yard, but you can’t make your yard work with just any robot.

1. Boundaries and navigation

Robot lawn mowers use different types of navigation technology that have evolved with the help of artificial intelligence (AI), improved processors and sensors, and more capable algorithms.

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Here are the different types of navigation that robot mowers use:

Wired boundary

A robot mower with a wired boundary is the oldest navigation technology for this type of device. With this technology, you bury a boundary wire around the perimeter of your lawn. The robot mower is engineered not to cross this wire, so it stays within that physical boundary.

• Pros: The physical boundary offers reliable navigation. It’s also become inexpensive as other technologies have grown more popular.
• Cons: Setting up a boundary wire is labor-intensive compared with other options.

Best wired boundary robot mowers:

GPS/NetRTK navigation

Some robot mowers use satellite navigation to create and stick to a map, which is a better option for larger yards than wire boundaries. While GPS/RTK robot mowers initially used an antenna for satellite connectivity, newer NetRTK technology means robots no longer require a separate antenna. This change simplifies the robot mower’s setup process.

NetRTK uses a network of fixed GPS stations to help the robot make quick corrections and maintain a map’s accuracy within a couple of inches. Instead of relying on a single GPS base antenna, NetRTK uses multiple stations to cross-check the robot’s location in real time.

• Pros: GPS antennas aren’t as labor-intensive to set up as wired boundaries. Newer models don’t require antennas.
• Cons: While setup is easier, GPS/RTK antennas require a relatively clear view of the sky and can be the most expensive navigation type.

Best GPS/NetRTK robot mowers:

Visual navigation

The latest navigation technology for robot mowers combines LiDAR sensors, cameras, and AI algorithms to enable the robot to respond to its surroundings in real time. This type of “drop-and-mow” navigation tech is the easiest to set up of all, as it typically only requires plugging in the mower and adding it to the app to map your yard.

• Pros: Without a wire or an antenna, these robots are less expensive and easier to set up than GPS and NetRTK models.
• Cons: This technology is still evolving, so you may encounter issues with the robot drifting out of your yard or into areas it shouldn’t go, such as garden beds.

Best visual navigation robot mowers:

2. Price and budget

Your budget can significantly narrow down the list of robot mowers you choose. Consider when a robot lawn mower makes sense, like when you already pay for lawn service for a medium or large yard, and when it may not, like if you have a small lawn and actually enjoy cutting it.

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A robot lawn mower can be budget-friendly ($500-$1,000), midrange ($1,000-$2,000), or premium/high-end ($2,000-$6,000).

3. Size of your yard

Robot mowers are designed with different specifications to cover a determined acreage in a single day. That doesn’t mean they’ll do it on a single charge, but each has a certain battery size that, combined with the cutting width, should be able to cover an area within a day’s work.

Find out the size of your lot, not your home’s footprint, to determine which robot mower is best for you. Most US suburban home lots are 0.25-0.5 acres. The lot size for your home is listed on land surveys, but you can also look up your home address on real estate sites, like Zillow and Realtor. These sites include the home’s acreage in the description, which is useful if you’re a renter.

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Here are some of the top-performing models that I recommend in each size category:

0.10-0.25 acres

0.25-0.75 acres

0.75-1.25 acres

4. Yard terrain

As I mentioned above, the way your yard is built will be the determining factor in which robot mower you buy. Hilly terrain can be a big challenge for robot lawn mowers and will likely require a model with all-wheel drive, for example.

Flat or gently sloped yards

Many inexpensive robot mowers are well-suited to handle flat or even gently sloped yards. These robot mowers perform well on mostly flat lawns:

Uneven terrain

A yard with multiple slopes, trees, and overall rough terrain requires a mower that can handle unevenness without sliding or getting stuck. Multiple areas in my yard have proved challenging for multiple robot mowers, but here’s an AWD option that works on rough terrain:

Multiple sections in a yard

While robot mowers work best in a single continuous space, many yards have multiple sections. Here are some examples of robots that have done well in my sectioned yard:

5. Obstacles

The obstacles in your yard can help narrow your choices for a robot mower, as they largely determine the type of navigation best suited to you.

For example, a LiDAR robot mower can do a good enough job of navigating your yard, but it may not be ideal for yards without fences or for yards with garden beds without physical borders. Some LiDAR models will stick to your map, but this type of navigation isn’t as reliable as wired boundaries.

Yards without many obstacles, like rocks, trees, toys, pets, and garden beds, do well with most types of robot mowers, provided that they are suited to handle the terrain accordingly.

Considering obstacles, here is what I recommend:

6. Ease of use and maintenance

How easy your robot mower is to use and maintain is crucial when choosing a model. Most people who buy robot lawn mowers want a device that makes the grass-cutting task easier, not harder. Research the mower’s reviews and what users say about the apps that control them before checking out your online cart.

From the setup, mapping, and installation to the application, maintenance, and remote operation, any robot lawn mower you choose must fit into your routine and your level of tech-savviness.

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The level of involvement you want in your robot mower’s maintenance will largely depend on your choice. You’ll have to replace the mower’s blades every one or two months, depending on usage. It’s also important to clean your mower a few times per season, with some models allowing you to use water hoses to do so.