Patent ID: 8182579

Claim:
A system for determining an air purifier filter change time, the system comprising: a motor speed measurement unit configured to measure a rotational speed of a motor that operates a filter provided in the air purifier; a time counting unit configured to count time starting from the point when the motor starts rotating upon receiving power supplied thereto or from a point when power supplied to the motor is cut off; a speed determination unit configured to check whether or not the rotational speed of the motor has reached a pre-set speed; a time comparison unit configured to receive information regarding recorded motor running time from the time counting unit and comparing the recorded motor running time to a pre-set time duration, if the speed determination unit determines that the rotational speed of the motor has reached the pre-set speed; and a filter change time determination unit configured to check whether or not a filter change is required according to results obtained by comparing the time duration during which the rotational speed of the motor has reached the pre-set speed with the pre-set time duration.