The evolution of compact heat exchangers was driven by the need for reducing their size and weight and enhancing individual components and overall system performance. These needs are also becoming relevant in stationary refrigeration and air conditioning applications. The reduction in volume and footprint of the systems is foremost in the minds of urban architects, while refrigerant charge reduction and performance enhancement remain important safety and operating considerations. Minichannels provide a viable solution to address these concerns and are expected to be used widely in large as well as small commercial, industrial, and residential systems. This paper provides a roadmap for their implementation, with a critical review of the current status of our understanding in this field, recommendations for obtaining fundamental performance data and correlations, and an emphasis on innovative designs of minichannel heat exchangers.