This paper presents an overview of the reasons for charge reduction in air conditioning and refrigeration systems and discusses strategies for charge reduction: in compressors (oil), vessels, pipes, and heat exchangers. The focus is on heat exchangers, microchannel in particular. In addition to a trivial reduction of internal volume as a strategy for charge reduction, the effect of mass flux on void fraction and needed manipulation of circuiting is presented. A framework and example of comparison between refrigerants based on their potential for low condenser charge is provided.