Abstract: An evaporator coil heat exchanger assembly of a refrigeration system, such as a transport refrigeration system, which includes an electrical heating element for rapid defrosting of the evaporator coil with its attendant refrigerant carrying tubes and cooling fins. The electrical heating element is quickly attached to the collective edges of the cooling fins by a plurality of low cost spring retainer clips which have one portion which extends between two closely spaced cooling fins to hook a refrigerant carrying tube, and another portion which holds the heating element against edges of the cooling fins with a spring force. The spring retainer clips may be just as quickly removed should the heating element require replacement. Each spring retainer clip is formed from a single piece of metallic wire having first and second curved end sections, and an intermediate portion which functions both as a spring and as a handle.