A large calorimetric neutrino mass experiment using thermal detectors is
expected to play a crucial role in the challenge for directly assessing the
neutrino mass. We discuss and compare here two approaches to the estimation of
the experimental sensitivity of such an experiment. The first method uses an
analytic formulation and allows to readily obtain a sensible estimate over a
wide range of experimental configurations. The second method is based on a
frequentist Montecarlo technique and is more precise and reliable. The
Montecarlo approach is then exploited to study the main sources of systematic
uncertainties peculiar to calorimetric experiments. Finally, the tools are
applied to investigate the optimal experimental configuration for a
calorimetric experiment with Rhenium based thermal detectors.Comment: 25 pagers, 16 figure