A method for continuous condition monitoring of an electric motor having a rotor and a stator and at least two motor phases, wherein, a first energy loss is associated with the first motor phase and a second energy loss is associated with the second motor phase. The temperature during operation of the electric motor is determined by firstly carrying out a first temperature calculation in order to estimate a temperature of the first motor phase, the first temperature calculation incorporating an energy loss estimation, and a temperature estimation in which a temperature of the first motor phase depends on the estimated energy loss. A second temperature calculation in order to estimate a temperature of the second motor phase utilizes the first temperature value and an energy loss difference between the first and the second energy loss.