A decision support model for improving a multi-family housing complex based on CO2 emission from gas energy consumption

► Decision support model can reduce CO2 emission by gas energy of apartment complex. ► The model can select the complex with the most potential in terms of energy-saving. ► Cluster-based CBR model applied with GA improved the prediction accuracy at 93.47%. ► Using the model, a decision maker can reduce the rate of CO2 emission beyond 5.36%. ► The model can make the improvement program for apartment complex more effective.