Abstract Formalism is proposed for studying of the thermodynamic properties of ferromagnetic nanowires, on the basis of which it is established that at temperatures below the Debye temperature the contribution of a domain wall to the heat capacity of ferrite-garnet nanowires can exceed the phonon and magnon contributions. The conditions for realization of this phenomenon are determined. It is shown that this effect has a nanoscale nature. It is found that by varying the magnitude of the nanowire magnetization it is possible to influence its temperature and dimensional characteristics.