Is it worth getting a robotic lawnmower?

If mowing the lawn is eating into precious time after work or during weekends, you may have flirted with the idea of going robotic.

You don't have to look far to find robot lawnmowers; many major electronics and hardware retailers are now selling the devices, which start from about $500.

But are they worth the investment?

How do robot lawnmowers work?

Australia's peak consumer advocacy group Choice has been researching robot lawnmowers.

Director of testing Matthew Steen says the devices are generally controlled through an app on a smartphone and have a powered docking station where they charge.

"The newer models use geofencing, which is similar to a GPS in a car. Basically, it's just a way of calculating the size of your yard and any particular things in the way, like trees," he says.

Some models also use LiDAR (light detection and ranging) and AI (artificial intelligence), which take something called "continual image mapping".

"A robot lawnmower will go around any toys or trees or bushes because [it knows] it will get stuck."

Lawn care expert Dallas "Rusty" Garton, from the northern Gold Coast/Yugambeh lands, says some older models require the installation of a boundary wire on the perimeter of the property.

"Those models don't have that obstacle detection and AI vision, so they could get hung up on a garden hose or a dog toy," he says.

He says robotic lawnmowers put grass clippings back onto the lawn rather than catch them, so they work best when they are used frequently.

"If you've allowed the lawn to grow for two to three weeks and you send your robotic mower out, they're useless."

What if I live on a residential block?

Residential robot lawnmowers typically cover block sizes from 250 square metres up to 1,000sqm, according to Choice.

The type of features you need depends on whether your yard is flat or undulating and how much you want to spend.

These can cost up to a couple of thousand dollars, depending on the technology.

"If your lawn is on a slope, it's important to work out the angle and make sure the model can cope with it," Mr Steen says.

Mr Garton has used the same robotic lawnmower for the past five years to maintain 350 square metres of turf in his backyard.

"They are set and forget," he says.

"You can configure them on the app to the size of your lawn, and you can split it up into different areas.

"I could have it mowing at 11pm and no-one would even know [because they are so quiet] and they leave a beautiful, clean cut."

Mr Steen recommends monitoring the mower the first time you use it to make sure it isn't getting stuck anywhere, and to check that it reaches all parts of your lawn.

"From that point on, it should be fairly autonomous, at least until you need to replace the batteries or have the blades sharpened or replaced," he says.

What if I have an acreage block?

Choice says some robotic lawnmowers are designed for lawns up to 5,000sqm, but they generally have a larger price tag.

"The maximum stated capacity of a robot mower we've tested was 3,000sqm," Mr Steen says.

"If you select a robot lawnmower that's designed for a smaller yard than what you have, the mower is going to run out of puff and need to return to charge before finishing the job."

He says manufacturers recommend buying a model that's suitable for a yard slightly larger than your own.

"Then they get quite expensive, around $6,000," Mr Steen says.

Peter French bought a robotic lawnmower to help maintain his 3,000sqm yard in Theodore in Central Queensland.

The retired cotton farmer spent months researching devices before deciding on one designed for 5,000sq m blocks.

"It tracks via satellites, the same as when we're farming with tractors," he says.

"You can map out your lawn and when you've got trees and things like that, you can set a no-go zone, so it knows there's something there."

But while the accuracy of the robot worked "extremely well", Mr French says it has struggled on dewy or irrigated grass.

"At least weekly, you had to basically tip it upside down and clean out all the wet clippings."

He says he was hoping to upgrade parts on the robot but is having trouble getting them from the manufacturer.

Features to look out for

If you're going to invest in a robot lawnmower, Choice recommends looking for one that offers a long warranty.

"It [generally] means the manufacturer has trust in their product," Mr Steen says.

"And look at their websites to see if they have parts available.

"Also, if a manufacturer's got robot vacuums and they perform well on apps, they often port the [technology] across to their robot lawnmowers."

He recommends also looking for devices with removable batteries.

"Then you can replace it really easily, because after a couple of 1,000 revolutions of the battery, you're going to get a decrease in efficiency."

Most robot lawnmowers have in-built safety features such as lift and bumper sensors, retractable blades and emergency stop buttons.

But Choice recommends making sure there are no children or pets in the yard when a robotic lawnmower is in use.

"Even though we haven't seen a documented case of a pet's tail getting cut or robot lawnmowers climbing up a shoe, there's no reason to tempt fate," Mr Steen says.

Mr Garton also recommends picking up dog waste from the lawn before the mower is used.