This study is aimed at investigating the potential of the refrigerant vapor injection (VI) technique to improve the energy efficiency of air-conditioning (AC) systems in hot climates, with a focus on Kuwait’s sustainability goals for 2035. The VI technique was found to significantly enhance heating and cooling systems by lowering compressor discharge temperature and improving cooling capacity, resulting in an enhanced coefficient of performance (COP). Data from previous experimental studies were analyzed to correlate the VI technique’s cooling COP with operating conditions at high ambient temperatures ranging from 20°C to 52°C. The results showed that the VI technique was applicable at high ambient temperatures, leading to improvements of up to 35.4% compared to conventional cooling systems. Empirical formulas, comprised of the temperature parameters (ambient, wet bulb, condensation, and evaporation temperatures), were developed to predict the COP of the VI cooling cycles with a maximum mean absolute error (MAE) of 3.81%. The results also showed that the VI technique enhanced the cooling COP by up to 28% when operating at 51.7°C and up to 34% during the hottest month in Kuwait (July) compared to the conventional cooling cycle. The empirical correlations were also applied to other Gulf Cooperation Council (GCC) countries to examine the impact of ambient humidity on cooling COP, with predicted increases ranging from 13.5% to 21.2%. Further experimental studies are recommended to fully evaluate the cooling impact of the VI system in GCC countries.