The diploma thesis deals with the solutions of the renovation of a panel apartment building with regard to energy efficiency. The theoretical part deals with heat pumps. The acquired knowledge was subsequently applied in the computational part, where the energy assessment of the current state of the apartment building and the design of two possible variants of renovation are addressed. The aim of the first variant is the renovation of the building to meet classification class C using the possible funds. The second variant is focused on the technical equipment of the building and primary energy from renewable sources, so that the apartment building reaches classification class A. Both proposed variants are assessed from both an energy and financial point of view. The project part then contains certificates of energy intensity of individual variants of the building.