Abstract: In a furnace of the type having a blower shelf with a blower attached to one surface thereof and a heat exchanger unit located proximate a second surface thereof, and the heat exchanger unit being reversibly attachable to the blower shelf, the improvement comprising: a retaining structure unitary with the back panel of the heat exchanger; and a structure which mates with the retaining structure and is unitary with the blower shelf. The retaining structure and mating structure function jointly to retain the back panel of the heat exchanger unit perpendicular to and proximate the blower shelf.

Abstract: A filter retaining device for a furnace having a casing and requiring a filter includes a filter retaining wire for securing the filter over an opening provided in the casing. The retaining device also includes a latch clip and a retainer clip which are each insertable through a corresponding hole in the furnace casing. One end of the filter wire is moveably secured by the retainer clip. The other end of the filter wire has a U-shape formed therein so that it can be easily snapped into and out of the latch clip. Each clip has a pair of flexible barbed detentes so that it may be securely snapped into its corresponding hole.