This research presents an energy efficiency improvement solution for supermarkets with the use of low-E glass doors for open refrigerators and a digital semi-hermetic compressor to fix the speed of semi-hermetic compressors. The impact of a door’s installation causes its load to be reduced by 40%, and the compressor shuts down frequently, which decreases its lifetime. In order to ensure that energy-saving solutions do not affect maintenance costs, the installation of a digital semi-hermetic compressor is proposed to lower costs and save energy. Our economic results from tests carried out at a 3000 square meter supermarket, which was open from 6:00 a.m. to 12:00 a.m. and in which we installed 82 doors on 15 open refrigerators, showed a 1.1-year payback period with an energy saving rate of 192,220 kWh/year for store No.1 (R22) and in which we installed 80 doors on 15 open refrigerators, showed a 1.4-year payback period with an energy saving rate of 171,185 kWh/year for store No.2 (R404A). The energy-saving effects of the digital semi-hermetic compressor, which fixes the speed of the semi-compressor and solves the problem of impact from fridge door installation, showed a 2.9-year payback period with an energy saving rate of 26,890 kWh/year for store No.1 (R22) and showed a 2.9-year payback period with an energy saving rate of 26,571 kWh/year for store No.2 (R404A). The results of store No.1 (R22) and store No.2 (R404A) showed no differences. This research is an extension of an energy-saving project that can be carried out on a continuous basis, increasing the efficiency of energy use and being a sustainable source of energy conservation.