3. Virtual wall
An accessory is used to create an invisible barrier to block off open doorways or other areas you don’t want the robot to enter. Many robot vacuums will define the virtual wall using an app, but some use infrared towers to define barriers (these may cost extra).
4. Automatic docking
When the battery charge is low the robot vacuum finds its way back to the charger and docks automatically. All the models in our test do this.
5. Running time
Battery life is important, especially if you have a large area to be cleaned. You’ll want a robot vacuum that cleans for long enough to cover your floor area before returning to the charging station. While we’re seeing battery life improving, we’ve noticed some models that keep running well after the motor has actually stopped ‘cleaning’. Essentially, these vacuums have a cleaning mode and a return to charging station mode. In these cases, we measure the running time to be until the motor stops running (i.e. cleaning has stopped).