This Bachelor’s Thesis is engaged in an assessment of investments into a family house heating system. The first part describes a model house chosen for this work. Further, it states a method of the calculation of the peripheral wall and void filling heat loss. The values are then used to determine the heat output. The work recommends the use of different insulation materials and options for void filling replacement to comply with the requirements for obtaining a grant. According to the calculated heat output, it suggests a choice of more effective and ecological sources for heating, which could replace the current source.In the conclusion of this work, the results are graphically processed and evaluated according to the estimated return of ...