Taiwan is located in the subtropical zone where the summers are hot and humid. The demand for comfort and quality of life in this zone is increasing. Air conditioning equipment in Taiwan has transformed from a luxury item into a basic necessity, resulting in a growing demand for small, consumer air conditioning units. Attractive, low-noise, small, and split-type air conditioning systems have become popular in the residential air conditioning equipment market. In this study, we used a heat recovery system to recover heat from air to increase the system hot and cold side efficiency and reduce the carbon footprint of smart buildings. The improved wall mounted evaporator combined with a central monitoring system is different from the typical AC unit evaporator that makes the system much more efficient.