A capacitive sensor system for detecting accumulation of dust in a filter of a HVAC system includes a first conductive mesh, a second conductive mesh, a first filter media disposed between the first conductive mesh and the second conductive mesh, and a circuit configured to measure a capacitance of a first capacitive sensor formed by the first conductive mesh, second conductive mesh, and the first filter media. The circuit further is configured to translate a measured capacitance to a dust level indicator frequency that is used to determine a frequency corresponding to level of dust.