Care for the maintenance of apartment buildings represents a significant part of the housing management. Unlike detached houses, where the decision on the renovation is usually tied to a single owner in apartment buildings the decision-making is the responsibility of all the apartment owners. The first part of the thesis is focused on on the presentation of legislation in the field of housing management and rules that need to be respected by apartment owners in order that the building serves its purpose. In the second part of the thesis, housing fund in the City municipality of Ljubljana is presented, together with the maintenance requirements for apartment buildings. The role of the housing manager and apartment owners in the process of management and maintenance of the building is also described. In the third part of the thesis, an example of the apartment building energy renovation is shown. The provision of financial resources for energy renovation of the apartment building are described as well as the preparation of a maintenance plan for the building, the decision-making process of the apartment owners, the process of selecting the contractor of renovation and the role of housing manager in the process. The financial structure of the investment in energy renovation of the apartment building and analysis of the cost savings for residential heating are presented at the end of the thesis.