How do you recognize a faulty appliance by its electricity consumption?

The metering system splits consumption per dwelling into four groups, allowing you to identify anomalous patterns, such as a climate group that never drops to zero at night or when vacant. Usage by guests varies; a faulty device ignores this variation and instead consumes constantly or at times when nobody is home. The guest themselves can also notice something unusual via their live consumption and report it. The system only provides an indication that something is off, not an exact diagnosis; for that, a technician is still needed.