A disposable filter for heating and ventilating registers wherein a supporting framework includes apertures with removable cover portions which permit selective air flow, means for securing the framework to the register or adjacent structural members and re-closable means for admitting a filter element to an interior cavity. In alternative configurations, differing filter media or replacement media may be mounted to the framework. A separately attached border trim may also be included for oversize registers. Also considered is a finish cover including means for retaining the filter to the cover and the cover to the ductwork port.

A air filtering assembly for removing particulate matter from air supplied through HVAC ducts. The air filtering assembly includes a frame assembly including a connection assembly adapted for coupling to an air vent, and an air filter couplable to the frame assembly and positioned adjacent to the air vent for filtering the air directed through the air vent.

Disclosed is a porous device adapted to remove particulates from a fluid passed through the device. The device includes a porous filtration medium. The medium has a first surface having an area which is adapted to receive the fluid for passage through the medium and a second surface from which the fluid exits the medium. The device is configured to variably increase the area of the first surface in response to a differential in fluid pressure between the first surface and the second surface so as to extend the life of the device. In some embodiments the device is adapted to retain the increase in surface area which acts as a visual indication that the device is reaching its capacity to retain particulates.

A filter frame formed from a stock channel member having a generally U-shaped cross-sectional configuration. The channel member may be provided in stock lengths which may be cut on-site to the desired size to form each side of a filter frame when assembled together. The cut lengths of the channel members may be assembled together in the appropriate configuration to match the filter being replaced, and a mass of filter medium cut to a corresponding configuration and placed within the cavity formed by the u-shaped cross-section of the channel members to form the air filter. The channel members are also provided with a plurality of U-shaped grooves in the upstanding legs of the channel members which form tabs. The tabs may be advantageously employed with a length of elongated material to form a protective screen. Specifically, a length of elongated material, such as string, may be wound about the tabs and across the length of the air filter to be wound through separate tabs. Repeating this process forms a substantially taught web of the elongated material which functions as a protective screen to maintain the filter medium in position.

The invention provides a filter that can be cut-to-fit or deformed to fit a variety of differently shaped and sized intakes. The invention also provides a filter kit that allows a user to create a filter of a desired size with attaching mechanisms to secure the filter to or on the intake.