  Context. Radiative losses are an indispensable part in the numerical
simulation of flares. Detailed calculations could be computationally expensive,
especially in the chromosphere. There have been some approximate recipes for
chromospheric radiative losses in flares, yet their feasibility in flare
simulations needs further evaluation.
  Aims. We aim to evaluate the performance of different recipes for
chromospheric radiative losses in flare simulations.
  Methods. We compare the atmospheric structure and line profiles in
beam-heated flares calculated with detailed radiative losses and the
approximate recipes.
  Results. Both GF90 and HCD22 recipes provide acceptable total radiative
losses compared with detailed one, but there are discrepancies in the different
atmospheric layers during the different evolutionary phases, which leads to
misestimations of temperature and line intensity. The recipe of GF90
overestimates the coolings in the upper chromosphere greatly when temperature
exceeds 10^5 K, which also affects the flare evolution and line asymmetries.
Radiative heating in the middle chromosphere only functions in the initial
stage and could be safely neglected. However, radiative heating from Lyman
continuum could dominate near the transition region.
