As climate change concerns are rising rapidly, energy efficiency promotion and implementation could be sustainable solutions within energy transition. In this context, buildings, including educational ones, play an important role in reducing energy needs and promoting energy efficiency since they account for a significant share of the total energy consumption. As a case study for this research, the educational building of Kazakh-German University was selected. Following the national and international building standards, energy performance parameters were estimated. Current heat losses and performance have been estimated as baseline scenario settings. The impact of retrofitting measures on energy efficiency performance of the buildings under the four scenarios was calculated. Under the minor scenario, retrofitting interventions will lead to annual energy savings of 36.9 kWh/m2 and a 48% CO2 emission reduction, whereas under the major scenario, the annual energy savings will increase to 77.76 kWh/m2 and a nearly 82% CO2 emission reduction. The integration of a solar thermal system with capacity 400 kWh, assuming that the heat demand was reduced under the minor retrofitting scenario, can decrease heat energy consumption and CO2 emissions to 35%. As upfront costs of the energy efficiency measures are high, a carbon offset mechanism could facilitate the implementation of university building modernization.