The object of research. A comparative analysis of software that allows the carbon footprint of a projected building to be determined at an early stage in terms of functionality has been carried out. A description of the software and services under consideration and their advantages are given. Carbon emissions for the building envelope of the building under renovation are assessed. A recommendation is made for a rational combination of building envelope layers with minimal impact on the environment. Results. It was revealed that the emission readings of the same material may differ by a factor of 2 to 3 depending on the composition, additives, manufacturer and combination of the structure. The use of energy-efficiency materials is one of the keys to a sustainable system.