With the advent of high efficiency air-conditioning and heat pump systems, achieving even higher seasonal efficiency is becoming more complex and incremental in nature. For this reason, component modifications that provide improvements of even a few percent can become very attractive. If these component level improvements can also provide secondary benefits, such as a reduced bill of materials or more compact packaging, the likelihood of acceptance and market penetration becomes high. One example of such a component level improvement is the novel integration of a stepper motor controlled electronic expansion valve with the distributor for a multi-circuited round tube plate fin heat exchanger. This paper describes the experimental validation of the potential improvements in seasonal performance achieved by implementing this novel electronic expansion valve design into a high efficiency reversible 3-ton air-conditioning/heat pump system. The implementation of this technology led to increases of nearly 5% and 3% in SEER and HSPF, respectively.