The results of mathematical modeling of heating mains laid out without canals, as well as numerical analysis of their heat losses in the presence of ground freezing in the area of installation are presented. The laws of heat transfer in the system and the factors influencing the intensification of heat losses are established. It was revealed that the regulatory calculation method of pipelines’ heat losses gives overestimated values. It was found that the heat losses of pipelines subject to ground freezing in the laying zone rise by 1.65–5.04%. The deviation between the heat losses of pipelines is about 21–27%, taking into account the freezing ground in the laying zone and heat losses, calculated according to standard methods. That indicates the need to adjust the regulatory procedure. These results suggest promising application of the developed approach to the analysis of thermal conditions and heat loss of heating mains laid out without canals in conditions of freezing ground in the laying zone and the possibility of its use in the creation of energy efficient heat transfer system.