Nowadays, European Directives and National laws impose more and more strict limits on the primary energy consumption of buildings, pushing towards a new generation of energy saving buildings named Near Zero Energy Buildings (NZEB). In order to achieve an important reduction of the primary energy consumptions in NZEB the use of renewable energy, which gives a discontinuous contribution during the day and the season, is strongly encouraged; due to the typical unsteady behaviour of renewable energies, for an accurate analysis of the behaviour of NZEB it becomes important to study the dynamic interactions between the building and the adopted HVAC system. A dynamic analysis of the energy performances of NZEB can be obtained by using specific dynamic simulation software (i.e. TRNSYS, ESP-r, Energy Plus, MODELICA, DesignBuilder) or by using a customized approach based on the use of SIMULINK. In the past, some open block libraries made in SIMULINK have been proposed for the dynamic analysis of HVAC system. However, a weak point of these libraries is the creation of the building model. In fact, no fully satisfactory SIMULINK blocks for the accurate modelling of a whole building have been presented up to now; in many cases, the user is called to add manually all the envelope elements by setting the thermo-physical properties of each element and connecting each element to the others. In this way, the modelling of a building becomes not only time consuming but it becomes an activity characterized by a significant probability to make mistakes during the manual construction of the whole model. For this reasons, in this paper a new SIMULINK library, named ALMABuild, for the dynamic modelling of the energy behaviour of a building is presented. The strength point of ALMABuild is that the user is driven towards the modelling of the building by means of a series of Graphical User Interfaces (GUI). In this paper the main results obtained during the benchmark of this library, following the BESTEST procedure, are discussed and the main advantages achieved by using GUIs for the creation of the dynamic building model are described.