Energy analysis of Erzurum Airport terminal building and investigation of retrofitting it to net zero energy building

40% of the energy used worldwide is consumed in buildings, and it is well known that measures and changes in the buildings can yield substantial savings in energy. Net-zero energy buildings (nZEB) produce as much energy as they consume over a defined period, significantly reduce building energy use and enable buildings to become energy self-sufficient. The main objectives of this study are to analysis the energy performance characteristics of Erzurum Airport Terminal Building, located in the coldest climate of Turkey and to convert it net zero energy building. The building was simulated with real insulation levels, heating, ventilation, and air conditioning (HVAC) equipment, and appliances by using EnergyPlus building energy simulation software. A comparison is made between the real energy consumption and the energy consumption by simulation of the Terminal Building. Decreasing the energy demand of the building and then the integration of renewable energy into building designs are examined and evaluated in energy and economic terms. The value of employing each measures and changes was explored. The results showed that the retrofitting Erzurum Airport Terminal Building to net zero energy building can lead to substantial energy saving and CO2 emission decrease.