Abstract The hopping transport model (Phys. Rev. B 12 (1975) 680) for vertical transport in superlattices has been extended towards a self-consistent calculation of the Wannier–Stark state distribution functions for plane–parallel electron motion. This way, the influence of field-induced electron heating could be investigated in the negative differential conductivity regime of nonequilibrium hopping transport. Variations of the mean electron temperature are observed near the optical phonon resonance which occurs if the Wannier–Stark ladder spacing is equal to the LO phonon energy.