What might indicate that an electric thermostat is malfunctioning?

Inconsistent temperature readings and heating cycles are a strong indicator that an electric thermostat may be malfunctioning. A properly functioning thermostat should accurately sense the temperature of the environment and respond by activating or deactivating the heating system to maintain the desired temperature setpoint. When the thermostat is working correctly, it should provide stable and consistent temperature readings, leading to predictable and regular heating cycles.

If the thermostat is experiencing issues, it might display erratic temperature readings, which could result in the heating system cycling on and off more frequently than necessary, or failing to activate when needed. This inconsistency can cause discomfort in the conditioned space, reflect poor temperature control, and indicate underlying mechanical or electronic failures within the thermostat itself.

The other options do not effectively represent symptoms of thermostat malfunction. Consistent temperature readings suggest that the thermostat is functioning correctly, scheduled maintenance is a routine practice that does not indicate any immediate issues, and excessive energy consumption without a correlated change in heating may point to inefficiencies elsewhere in the heating system rather than directly identifying a problem with the thermostat.