A heat exchanger assembly for transferring heat between a refrigerant and a stream of air, comprising: a first manifold; a second manifold spaced from said first manifold; a plurality of tubes extending in spaced relationship with one another between said first and second manifolds (24, 26) for conveying the refrigerant between said first and second manifolds (24, 26); a plurality of fins disposed between adjacent ones of said tubes for transferring heat between the refrigerant in said tubes and the stream of air; each of said fins having a front edge and a back edge and including a plurality of legs extending transversely between said adjacent tubes; wherein each of said legs of said fins defining a plurality of front long louvers disposed between said front and back edges (44, 46) for conveying the stream of air through said legs of said air fins with each of said long louvers having a long louver height (H L) and a long louver length (L L); wherein each of said legs of said fins defining a plurality of main spoilers disposed between said front long louvers and said back edges (44, 46) for inducing turbulence in the stream of air with each of said main spoilers having a spoiler height (H S) in the range of 50 to 90 percent of said long louver height (H L) the heat exchanger assembly being characterized in that each of said main spoilers has a spoiler length (L S) in the range of 10 to 35 percent of said long louver length (L L), wherein said main spoilers are micro-louvers, and in that each of said legs of said air fins presents a plurality of front spoilers disposed between said front edge and said front long louvers for inducing turbulence in the stream of air, that each of said front spoilers extends outwardly from said legs and has a delta-wing shape or a triangular shape, the front spoilers being disposed over the entire fin height (Hf), and wherein the width and height of said front spoilers is comparable to the spoiler lengths (L S). a first manifold; a second manifold spaced from said first manifold; a plurality of tubes extending in spaced relationship with one another between said first and second manifolds (24, 26) for conveying the refrigerant between said first and second manifolds (24, 26); a plurality of fins disposed between adjacent ones of said tubes for transferring heat between the refrigerant in said tubes and the stream of air; each of said fins having a front edge and a back edge and including a plurality of legs extending transversely between said adjacent tubes; wherein each of said legs of said fins defining a plurality of front long louvers disposed between said front and back edges (44, 46) for conveying the stream of air through said legs of said air fins with each of said long louvers having a long louver height (H L) and a long louver length (L L); wherein each of said legs of said fins defining a plurality of main spoilers disposed between said front long louvers and said back edges (44, 46) for inducing turbulence in the stream of air with each of said main spoilers having a spoiler height (H S) in the range of 50 to 90 percent of said long louver height (H L) the heat exchanger assembly being characterized in that each of said main spoilers has a spoiler length (L S) in the range of 10 to 35 percent of said long louver length (L L), wherein said main spoilers are micro-louvers, and in that each of said legs of said air fins presents a plurality of front spoilers disposed between said front edge and said front long louvers for inducing turbulence in the stream of air, that each of said front spoilers extends outwardly from said legs and has a delta-wing shape or a triangular shape, the front spoilers being disposed over the entire fin height (Hf), and wherein the width and height of said front spoilers is comparable to the spoiler lengths (L S).