Actions contemplated in Sustainable Energy (and Climate) Action Plans (SEAPs), which municipalities adhering to the EU initiative called “The Covenant of Mayors” are required to prepare, regard many sectors, among which are buildings. To implement such plans, it is necessary to make use of methods for predicting energy use in buildings. Technicians involved in this tend to adopt easy-touse simulation models because of the common mid-level expertise of the offices involved. However, such simplified methods could result in a less accurate evaluation of the energy demand of buildings. In this paper the suitability of the quasi-steady state and the dynamic approach, in the frame of these new urban energy planning tools, is assessed. Specifically, a comparison between the two methods reported in the EN ISO 52016-1 Standard (namely the quasi-steady state monthly method and the dynamic hourly method), used here as representative of the two cited classes of models, is drawn. Despite some limitations of the quasi-steady state model found in the analysis, the possibility to still use both modelling approaches to implement SEAPs is argued in the paper. Moreover, a tentative procedural scheme is proposed, which technicians working on SEAPs can usefully follow in order to choose the most appropriate modelling approach that can be used depending on the specific situation to address.