In the case of Primary school Dobrova I checked what impact have actual thermal bridges on energy consumption for heating. From the plans of the building, I recorded all thermal bridges, which have affect on energy consumption. In standard SIST EN ISO 14683 I seek appropriate approximations to these thermal bridges. Then I made three simulations with the program TOST. In the first case I did not take thermal bridges into account. In the second case, I have taken them into account in a simplified manner and in the last case, I have taken them into account according to the SIST EN ISO 14683. Then I compared the results for all three cases with each other. Finally I made some steps how to reduce energy consumption. The results showed that the energy consumption due to thermal bridges increased by about 20%, comparing to SIST EN ISO 14683, regarding the case without taking them into account. In the case of a simplified method, the consumption increased by nearly 12%.