The paper presents the possibilities of increasing energy efficiency of sacral buildings. Churches in the Zawiercie pastoral district of the Archdiocese of Czestochowa have been used as examples of typical sacral buildings of low energy efficiency. Such structures need to be thermally insulated during their use. Certain possibilities of raising the energy efficiency of churches have been presented. The paper describes different systems: increasing of wall and roof insulation, installation of new windows, and modern heating systems. Installation of a new heating system has been considered the most effective and the easiest to be implemented one.