A filter system includes a housing having an inlet opening surrounded by a sealing surface, an outlet opening. The housing may be rotational molded or be configured to be nestable with additional housings for shipping purposes. The system may also be configured such that the filter to be mounted therewith can be placed interior to the filter housing during shipment. A V-bank filter or a single-header box filter is positioned in the inlet opening, has a flange in general alignment with the sealing surface, and a plurality of filter media sections projecting away from the flange and into the housing interior. A seal is disposed between the flange of the V-bank or single-header box filter and sealing surface. A pre-filter, such as a panel filter, may be provided upstream from the primary filter.