Airport terminal buildings consume more energy than other buildings in an airport due to their functional and operational characteristics. Heating, ventilation and air conditioning (HVAC) systems have been major energy consumers with a significant contribution to the annual total energy consumption in terminal buildings particularly in harsh climates. Therefore, improvement of energy efficiency of the HVAC system is becoming an increasingly important issue to reduce energy consumption and CO2 emissions of existing terminal buildings. The aim of this study is to analyze and evaluate the effect of various energy conservation strategies on energy consumption and CO2 emissions, including a number of modifications that can be applied to the HVAC system of airport terminal buildings. Erzurum Airport terminal building, located in the coldest climate zone of Turkey, was chosen as the airport terminal building. In order to achieve this goal, six strategies that can create energy savings and cost savings and provide environmental benefits were analyzed and evaluated by building energy simulation. The results indicated that energy consumption could be reduced from 6.3 GWh/year to 2.7 GWh/year and CO2 emissions from 1.9 million kg/year to 0.9 million kg/year by implementing feasible energy conservation strategies. This means that, by implementing the proposed energy-saving projects, energy consumption and CO2 emissions can be reduced by 57.24% and 48.79%, respectively. •HVAC systems are major energy consumers in airport terminal buildings.•Six strategies are proposed to reduce energy consumption of terminal buildings.•The effect of the strategies on energy consumption and CO2 emissions are analyzed.•Implementing feasible strategies save considerable energy and reduce emissions.