The article touches upon the problem of organizing a comprehensive thermal modernization of residential apartment buildings in Kazakhstan. The importance of solving this problem in terms of Kazakhstan's commitments to decarbonization and achieving carbon neutrality is substantiated, the main barriers and solutions are described. For the first time, the issue of thermal modernization of residential buildings is raised as a systemic process that affects not only buildings built 30–50 years ago, but also buildings currently being built, the stage of modernization of which will begin in the near future. Key recommendations are given for Kazakhstan on the organization of large-scale energy modernization, taking into account the accumulated international experience. The article was written within the framework of the project funded by the European Union "PROMHOUSE – Promoting professional housing management in Kazakhstan and Uzbekistan".