Wire vs Wire-Free: Which Robot Mower Do You Need?

Short answer: choose wire-free if your lawn has a decent view of the sky or clear features around it and you would rather not dig. Choose a boundary wire if your lawn is heavily shaded, your budget is tight, or you want the most predictable result in a tricky plot.

How a Boundary-Wire Mower Works

A thin cable runs round the edge of the lawn and around anything the mower must avoid, such as beds or a pond. The charging station sends a weak signal along it, and the mower senses that signal to know where to turn. Inside the loop it usually mows in a random pattern, covering the whole lawn over time.

Husqvarna's installation guidance gives a feel for the job. The wire is either pegged down about every 70 cm, after which grass grows over it, or buried 1–20 cm deep in a slit cut with a spade. It sits about 35 cm from walls and fences, and 10 cm from level paving. Which? suggests the install can be tricky and that it may be worth paying someone to do it.

How a Wire-Free Mower Works

Wire-free mowers draw the boundary in an app instead. You drive the mower round the edge with your phone, or let it map the lawn itself, and it remembers the shape. To know where it is, it uses one or more of:

• RTK satellite positioning, accurate to a few centimetres, using either an aerial in your garden or corrections sent over the internet ("network RTK").
• Cameras that recognise grass, edges and obstacles.
• LiDAR, a spinning laser that maps walls, fences and trees.

Most wire-free mowers mow in straight, striped lines rather than at random. Our navigation explainer compares the three technologies in detail.

Side by Side

What Goes Wrong with Each

Wire Breaks

The classic boundary-wire fault is a break, often from edging, digging, weather or animals. Husqvarna's "No loop signal" error usually means exactly that. Finding the break means testing the wire's resistance, or walking it. A wire also has to be re-laid when you redesign a bed.

Lost Signal and Lighting

Satellite mowers can lose accuracy near tall buildings and under large trees. Camera mowers can struggle in poor light, strong shadow, or where the lawn edge is unclear. LiDAR mowers have fewer reference points on a wide open lawn with nothing around it. Most current models combine two of these to cover the gaps.

The Middle Ground

Some ranges let you mix both. Husqvarna's NERA mowers can use virtual boundaries, physical wire, or a combination, so you can use wire only in the awkward shaded corner. That flexibility is rare and adds cost.

Which Should You Choose?

• Open lawn, some trees, any size: wire-free with RTK plus camera. See the best wire-free mowers.
• Lots of trees or tall walls: wire-free with LiDAR, or a boundary wire.
• Tight budget, small lawn: compare both; the cheapest models we track include wired and wire-free options. See under £1,000.
• You redesign the garden often: wire-free.

The market is moving towards wire-free. Analysts at Mordor Intelligence estimate that boundary wire still had the largest UK share in 2025, but forecast camera-based navigation to grow fastest. When you are ready to set one up, our wire-free setup guide covers mapping step by step.