Electric heat pump (EHP) systems are widely used for heating and cooling in small-scale shops. They are relatively easy to install and manage. Since 1998, KS C 9306 has been widely used for determining the heating and cooling capacities of EHPs. However, at present, to state with certainty that KS C 9306 is suitable for determining the optimal EHP capacity is difficult, as the standards employed for current building designs are considerably different. For example, the U-value standards for building constructions in 2022 are different from the standards applied in 1998. Studies on residential buildings have been actively conducted to determine the optimal heating and cooling capacities of EHPs; however, research on small-scale non-residential buildings is lacking. This study represents the first step in estimating the optimal heating and cooling capacities of EHPs in small-scale shops. The general design and building envelope information of small-scale shops was analyzed, after which reference models for small-scale shops were developed. For further research, 12 models according to the location, main direction, and U-values are proposed.