Reduction effect of greenhouse gas emissions from district cooling system by using waste heat from a cogeneration plant has received specific attention from the perspective of national energy and environmental policy, and was studied in this work. For each cooling system of a residential and commercial building, greenhouse gas emissions was estimated and compared to quantify reduction effect on emissions where the heat source of heat-powered cooling system was replaced with a cogeneration waste heat. In addition, to address the problem that the values of waste heat and CEF vary depending on variables such as national or geographical conditions, a general-purpose criterion to measure the utility of substituting a district cooling for a conventional system was suggested.