The analysis conducted in this paper was initiated by the fact that Serbia emitted around 80 million tons of CO2, equivalent in 1990, and in between 85-89 million tons in 2010, which places it among ten countries with the highest emission of CO2 per capita in the world (data by Cener for Ecology and Sustainable Development, Subotica, Serbia). This paper is aimed at making a correlation between the improvement of thermal performance of structural elements of buildings in order to enhance their energy efficiency, which is also economically justified, and reduction of GHG (CO2) emission whose economic benefits are not so easy to assess even though it represents an environmental problem. The case study analysis, presented by this paper, using the example of a select number of kindergartens in the territory of the city of Nis, Serbia, is aimed at determining the correlation of the effects of improvement of their energy performances on the reduction of GHG emission reduction by quantifying the benefits of CO2 emission reduction as a result of energy efficiency improvement reflected through the increase of energy class. The specific review conducted in this paper indicates the environmental importance of improvement of energy efficiency by valorizing the quantitative reduction of CO2 emission as a benefit of implementation of energy revitalization of buildings.