• Application of PCM TES for indoor environment control is presented. • From assessments made, 5% energy savings can be achieved by using PCM TES. • PCMs integration in AC unit enhance its coefficient of performance by ∼ 1.8% least. • Optimized PCM TES units can reduce CO 2 emissions by 30%. Phase change material thermal energy storage is a potent solution for energy savings in air conditioning applications. Wherefore thermal comfort is an essential aspect of the human life, air conditioning energy usages have soared significantly due to extreme climates, population growth and rising of living standards. Resultantly research efforts have shown increasing innovation towards the integration of phase change material based thermal energy storage technology with space heating/cooling systems to achieve significant savings. The review therefore focuses on the previous published experimental and theoretical works to organize these important milestones, analyze energy saving avenues as well as giving highlights on best practices and widely accepted techniques and recommendations for all reviewed studies to achieve cost cutting but accurate results. It also discusses the useful enhancements that can be implemented for optimum performance of the PCMs. The reviewed potential benefits of PCMs integration in air conditioning units include enhancements in the coefficient of performance by ∼1.8% at minimum, at least 5% energy savings and estimated reduction of CO 2 emissions by about 30%.