A timer that starts a time cycle when a filter is placed into a housing is
disclosed. The timer cycle will not reinitiate a new time cycle when the
previously used filter is removed from the housing and reinserted into
the housing. In one embodiment, the filter timer assembly includes a
filter having a filter media surrounded by a filter frame, a housing for
supporting the filter, a piercing post connected to the housing moveable
between a first resting position and a second position in direct contact
with the filter frame, and a timer connected to the piercing post. The
piercing post punctures a portion of the filter frame to create an
opening in the filter frame. The timer initiates a count when the
piercing post is actuated to the second position.