  Large calorimetric neutrino mass experiments using thermal detectors are
possibly going to play a crucial role in the challenge for assessing the
neutrino mass. This paper describe a tool based on Monte Carlo methods which
has been developed to estimate the statistical sensitivity of calorimetric
neutrino mass experiments using the 163-Ho electron capture decay. The tool is
applied to investigate the effect of various experimental parameters and the
results useful for designing an experiment with sub-eV sensitivity are given.
