The paper consists of two parts, theoretical and professional. The theoretical part describes the main principles and mechanisms of construction and operation of suspended ceilings. 2 commercially used suspended ceiling systems are described in more detail: fixed and modular. In the professional part of the paper, an assessment of the condition of the Elementary School Dušan Vukasović - Diogenes in Kupinovo was made, then an analysis of the energy performance of the school building and an assessment of the energy class was done. Measures for energy rehabilitation of the building were proposed and the calculation of energy efficiency was repeated. The significant energy savings were obtained and the building was classified in energy class C.