Using the technique of gaschromatography, the zero adsorption heats Q(o) were determined for 10 halogenated hydrocarbons and the corresponding n-paraffins with the same number of C-atoms on a zeolite of DY-type. The total substitution of H- by F-atoms in the n-alkanes results in an increase of the Q(o)-values as well as the substitution of F- by Cl-atoms in CF4. Simple equations are presented for the dependence of the zero adsorption heats at two different temperatures on the number of C-atoms for the n-paraffins. Calculated incremental heat values for the C-, H-, F- and the Cl-atoms allow for the calculation of Q(o)-values for different chloro- and fluoro-chlorohydrocarbons with sufficient accuracy for technical purposes.