Ventilation units with a filter shall be equipped with a visual filter change warning signal.

The filter change indicator is arranged to contact the interior filtering region of the filter, wherein when the predetermined bias force is reached, the filter change indicator is activated to notify a user to clean or replace the filter.

Lower maintenance as no oil changes or filters are required

A filter change indicator (64) is provided to communicate that a filter should be changed, and a filter orientation system (42) is provided to allow proper orientation of the filter with respect to the air flow.

The filter change indicator is arranged to contact the interior filtering region of the filter, wherein when the predetermined bias force is reached, the filter change indicator is activated to notify a user to clean or replace the filter.

The repair cost to re-assemble a filter is generally less than the cost of a new filter.

The operation has been satisfactory since the filter change.

Ventilation units with a filter shall be equipped with a visual filter change warning signal.

Filter changing knob (12): should change the filters.

A filter change indicator includes two indicators visible through a window.

An indicator (26) is provided to communicate that a filter should be changed, and a filter orientation (44) system is provided to allow proper orientation of the filter with respect to air flow.

A filter here and an oil change there will most likely suffice.

Like all air purifiers, the filters need to be changed.

Ventilation units with a filter shall be equipped with a visual filter change warning signal.

Ventilation units with a filter shall be equipped with a visual filter change warning signal.