A filter housing assembly (106) having a gas-tight seal and a method of replacing a filter are generally provided. In one embodiment, the filter housing assembly includes a housing (180) having an opening adapted to receive a filter (108) and an inlet. A seal member (302, 802) is coupled to the housing and is moveable between a first position and at least a second position, the second position sealing the inlet. The filter housing assembly may be configured to retain a roomside replaceable filter or have a filter permanently adhered within the opening.