U radu je izvršen izračun potrebne toplinske energije (referentne godišnje potrošnje toplinske energije) za grijanje stambene zgrada-obiteljske kuća u Slavonskom Brodu sa potrebnim ulaznim i izlaznim podacima za proračun. Potrebna toplinska energija za zgradu je ovisna o obliku građevine, konstrukcijskim materijalima, toplinskoj izolaciji, karakteristikama energetskih sustava i klimatskim uvjetima u kojima se zgrada nalazi. Kao energent za grijanje u navedenom primjeru je korišten prirodni plin, pa je za izračun potrošnje prirodnog plina (referentna godišnja potrošnja toplinske energije) uzeta prosječna potrošnja prirodnog plina od I/2013 do XII/2015. Budući da se u Hrvatskoj grijanje obiteljskih kuća provodi osim korištenjem prirodnog plina i primjenom ostalih energenata (električna energija, lož ulje, ukapljeni naftni plin, ogrjevno drvo, peleti), načinjena je usporedba godišnje potrošnje pojedinog energenta s obzirom na referentnu godišnju potrošnju toplinske energije za grijanje, kao i usporedba godišnje cijene pojedinog energenta. S ekološkog aspekta je načinjena i usporedba godišnje emisije CO2 pojedinog energenta u ovisnosti o faktoru emisije pojedinog energenta. ; In this work it was carried out the calculation of heat energy (the reference year consumption of thermal energy) which is used for heating residential buildings-family house in Slavonski Brod with the necessary input and output data for the calculation. The heat energy which is used for the building depends on the shape of the building, construction materials, thermal insulation, energy system characteristics and climatic conditions in which the building is situated. Natural gas is used as an energy source for heating in the above example, so for the purpose of calculation the consumption of natural gas (reference annual heat consumption) was taken the average consumption of natural gas from I / 2013 to XII / 2015. Since in Croatia heating family houses is carried out in addition to the use of natural gas and by applying other energy (electricity, fuel oil, liquefied petroleum gas, firewood, pellets .), so in this paper a comparison of annual consumption for each energy source was made with respect to the reference annual consumption of thermal energy for heating, as well as the comparison of the annual cost for each energy source. With respect to ecological aspect it was made a comparison of annual CO2 emissions of each energy source in relation to the emission factor of each energy source.