In the article the question of basement insulation of external walls of the large-block buildings with unheated basement. Proposed seven options of warming in this site. The temperature field and the heat transfer coefficients determined line built for the considered node. Separately, we consider the situation of the local thermal insulation in buildings, thermo past. A comparative analysis of insulation, found advantages and disadvantages of the proposed options. It was found that the additional insulation in the basement of the building with a basement reduces overall heat loss from the building only 1,0 ... 1,5% compared to the embodiment of thermo-insulation of the building without additional ground node. Thus, the insulation of the basement of the building with unheated basements significantly affect the overall heat loss from the building, and calls into question the appropriateness of the requirements for insulation basement units.