EN
The paper presents the analysis of the warm insulation profi tability of existing single-family buildings. The investigations embedded the external baffl es of the buildings from years 1958–2006. The analysis shows that external walls and a roof are the most crucial parts of building if considering a heat loss. As for a profi tability index NPV, due to its accuracy and the possibility of an additional estimation of results as well as despite the more complicated calculation procedures, this index should be treated in legal documents with the same importance as the SPBT index, being commonly used to determine variants of thermo-modernization. Moreover, the highest profi tability is shown by the investments with an additional warm-insulating coat in the buildings from years 1958–1979. The use of the insulation of optimal thickness, on walls – made of Styro-foam, whereas on roofs – of mineral wool, guarantees that the current norm requirements considering the warm insulation of building baffl es are fulfi lled in every cases.