Abstract Acoustic and magnetoacoustic waves are considered to be possible agents of chromospheric heating. We present a comparison of deposited acoustic energy flux with total integrated radiative losses in the middle chromosphere of the quiet Sun and a weak plage. The comparison is based on a consistent set of high-resolution observations acquired by the Interferometric Bidimensional Spectrometer instrument in the Ca ii 854.2 nm line. The deposited acoustic-flux energy is derived from Doppler velocities observed in the line core and a set of 1737 non-local thermodynamic equilibrium 1D hydrostatic semi-empirical models, which also provide the radiative losses. The models are obtained by scaling the temperature and column mass of five initial models by Vernazza et al. (1981; VAL) B–F to get the best fit of synthetic to observed profiles. We find that the deposited acoustic-flux energy in the quiet-Sun chromosphere balances 30%–50% of the energy released by radiation. In the plage, it contributes by 50%–60% in locations with vertical magnetic field and 70%–90% in regions where the magnetic field is inclined more than 50° to the solar surface normal.