Using the precision bomb combustion calorimeter B-08-MA, the combustion energies of 5-(4- nitrophenyl)-furan-2-carbaldehyde, 5-(2-methyl-4-nitrophenyl)-furan-2-carbaldehyde and 5-(2- oxymethyl-4-nitrophenyl)-furan-2-carbaldehyde. Based on the obtained data, the values of enthalpies of combustion and formation of substances in the condensed state are calculated. A comparative analysis of experimentally determined values with theoretically calculated values by additive calculation methods is given.