Abstract: An air filter having hollow support channels in its frame is disclosed. In one embodiment, the air filter comprises a support structure having a center portion and sidewalls positioned on opposite sides of the center portion, the center portion of the support structure attached to a side of a filter media, and a frame having a plurality of sections, each of the sections having a center portion and sidewalls positioned on opposite sides of the center portion, a first frame section attached to the support structure by connecting the sidewalls of first frame section to the sidewalls of the support structure to form a hollow channel between the first support structure center portion, the frame section center portion, and the sidewalls. Methods for cutting air filter sections and for attaching a frame to the air filter sections is also disclosed.