A pressure actuated electrical switch and indicator to indicate to a user that a filter vacuum cleaner requires cleaning or replacing. In a first embodiment, the pressure actuated electrical switch measures the pressure present between the filter media and the flow inducing device to determine whether a minimum absolute pressure threshold has been exceeded. The pressure actuated switch has a chamber with two electrical leads that are connected when the pressure in the vacuum cleaner raises above a predetermined level. A tube from the chamber to the vacuum cleaner housing draws a conductive part into contact with both leads. In additional embodiments, the pressure measure is the difference in air pressure above and below the filter media, or the difference in air pressure between the pressure in the air stream between the filter media and the flow inducing source, and the ambient air pressure.