Abstract
This research work investigates the impact of the choice of solar irradiation models on the hourly energy needs, considering 72 simplified reference buildings in two European climates: Rome and Vienna. The full combination of 22 horizontal diffuse irradiance models and 12 irradiance models for tilted surfaces has been considered for the development of hourly solar irradiation profiles, used as input in building energy simulation (i.e., TRNSYS). The results highlight that the variability of input solar irradiation leads to different levels of uncertainty in energy model predictions also depending on the building characteristics.