The disclosure relates to calibrating electric motors for use with a heating, ventilation and air conditioning (HVAC) system. Example embodiments include a method of calculating a correction factor for an electric motor (110), the method comprising: obtaining (206) at least one electric motor parameter of the electric motor (110); calculating (208) the correction factor for the electric motor (110) based on the at least one electric motor parameter, wherein calculating the correction factor comprises: determining an amount of electromagnetic torque produced by the electric motor (110); determining an amount of torque loss acting against the electric motor (110); and programming a motor controller (111) associated with the electric motor (110) with the correction factor.