The purpose of this paper is to compare a steady-state method for the calculation of solar heat gain entering a conditioned space through a sunspace according to EN ISO 13790, with results of dynamic simulation, through EnergyPlus program, in
order to better consider features like thermal properties of glazed envelope varying
with solar position, thermal properties of opaque envelope such as absorption and reflection coefficients, the inertia of opaque envelope etc. and their effects on the sunspace energy performance, both in winter and summer conditions. In order to
determine which parameters of the model have the strongest effect on the results, sensitivity analyses are carried out for an attached sunspace. Latitude, geometrical characteristics of the sunspaces, thermal characteristics of the transparent and opaque envelope have been chosen as the parameters of the sensitivity analyses