Abstract: A system and method for determining the condition of a filter in a forced air filtration system includes a blower motor and a fan mounted for rotation with an output shaft of the blower motor. A load sensor is operably connected to the blower motor for monitoring an electric load of the motor. As the filter becomes increasingly laden with airborne particles, the electric load changes. The load sensor generates a load value dependent on the electric load of the motor which is compared to a predetermined value. When the load value reaches the predetermined value, a signal is generated indicative of a filter change condition.

Abstract: An air purifier including a housing supporting an air inlet, an air outlet and an air flow passage interconnecting the air inlet and the air outlet. The airflow passage is defined by a filtration chamber positioned upstream from a blower chamber and an ultraviolet light chamber. A blower assembly is supported within the blower chamber and includes a fan driven by a motor for forcing air through the air flow passage from the air inlet to the air outlet. A pre-filter and a main filter are removably supported within the air filtration chamber for entrapping particulates having a size of 0.3 microns and greater. An ultraviolet light source is positioned within the light chamber and is positioned proximate the air outlet. An outlet grille is supported proximate the air outlet and provides for the passage of air while substantially preventing the passage of ultraviolet light. The outlet grille includes a louver assembly including a plurality of blades defining a plurality of convoluted passages.