A novel air filter and timer for alerting persons responsible for changing or
cleaning
the air filter that it is time for servicing. An audible alarm is provided on the
timer to emit a prolonged or intermittent audible alarm to indicate the need for
servicing. The alarm can be incorporated into the filter or made separately and
affixable to an air filter. The alarm sounds after a set time period to alert the
user to change the filter.
