A comparison between energy assessments in buildings carried out by means of both steady and transient states simulation methods

A comparison is presented between evaluations of building energetic consumption and thermal comfort using both stationary and transient building simulation models. As regards the former methods, the procedure reported in EN 832, the European standard in matter of energy consumption in buildings, is used; with reference to the latter ones, two models respectively based on the transfer functions (Energy Plus) and on the finite-difference (a code proposed by present authors) methods are used. The results obtained suggest to limit the use of stationary methods to seasonal energetic evaluations, where they show general accuracy; on the contrary caution should be used for monthly energetic evaluations and thermal comfort purposes.