Wire-free or buried wire: what you're really choosing

Every robot mower needs to know where your lawn ends. There are two broad ways of telling it, and the choice shapes your installation more than almost any other specification.

The two approaches

A buried boundary wire is a physical loop pegged or trenched around the perimeter of the mowing area. The mower detects the wire and turns back. It has been the standard approach for many years, and because it does not rely on satellite positioning, it is unaffected by tree cover or signal conditions.

A virtual boundary replaces that loop with a boundary the mower holds in software. How it does so varies by manufacturer: systems may use satellite positioning such as RTK-corrected GNSS, onboard cameras and computer vision, LiDAR, or some combination of these. “Virtual boundary” describes the outcome, not a single underlying technology — two wire-free mowers may work in quite different ways.

Here is what the models we track actually use.

Among the models we track, Husqvarna Automower 415X and Husqvarna Automower 435X AWD require a physical perimeter wire. The rest can be installed with a virtual boundary.

What each approach asks of you

Buried wire is unglamorous but predictable:

• Installation takes real time, and more of it on a large or complex lawn.
• The wire can be damaged. Aeration, edging, a fence post, or a determined dog can cut it, and locating a break is tedious.
• Changing the shape of your lawn means lifting and re-laying the wire.
• It does not depend on satellite reception.

Virtual boundaries trade that for a different set of considerations:

• The boundary is defined in software, so adjusting it does not involve digging. Whether initial setup is quicker overall depends on the system and the yard — some require a guided mapping run, and some require additional hardware to be sited first.
• Many require separate positioning hardware. This is the part buyers miss.
• Systems that depend on satellite positioning are affected by what can see the sky. Systems that lean more on cameras or LiDAR are affected by other things entirely, such as lighting and visual clutter.

The hardware nobody mentions

“Wire-free” reads like “nothing to install”, but many wire-free systems need a separate antenna or reference station positioned somewhere with a clear view of the sky — on a pole, a wall, or a roof. Manufacturers differ on how that unit is powered and connected, so check the specific model’s installation instructions rather than assuming.

Rather than generalize, here is the actual split across our dataset:

Where that column is blank, the manufacturer has not stated it. That is a question for the seller rather than a mark against the machine.

That hardware is a real installation requirement. If you rent, if you have an HOA with views on roof-mounted equipment, or if there is nowhere with a clear sky view, it deserves as much thought as burying a wire would.

Models that list both boundary types

Some manufacturers list both a physical wire and a virtual boundary for the same model. That means the model can be installed either way — it does not automatically mean the two can be combined in a single installation, or that the mower will fall back from one to the other. Whether a hybrid setup is supported is a model-specific question, and we only state it where a manufacturer documents it. Check the installation manual for the model you are considering.

If you are choosing between two specific models, put them side by side — the boundary, navigation, and antenna rows sit next to each other, and the blanks are as informative as the values.

How to decide

Two questions do most of the work:

1. Are you willing to bury a perimeter wire? If not, you are limited to models that support a virtual boundary.
2. Can you install the positioning hardware a virtual-boundary model requires? If there is nowhere suitable, wire-based models are the practical choice.

The selector asks both of these directly. Tell it you cannot install an antenna or reference station and it will rule out every model that requires one, naming the requirement rather than quietly dropping them.

“Positioning hardware” is no longer only a thing you mount. Some virtual-boundary models take their correction from the manufacturer’s own network instead, and a few use no satellite positioning at all. The selector treats those as separate questions, because being able to put up an antenna does not help a mower that was never going to use one.

Site conditions such as heavy tree cover are worth weighing too, especially for systems that depend on satellite positioning — but the selector does not currently ask about them, because we have no verified per-model data describing how each system copes. Treat that as a question for the manufacturer or seller.