The paper presents a methodology for quantifying the electrical flexibility potential of air-conditioning systems (ACS) installed in residential buildings according to the building envelope characteristics and the ACS performance. In order to provide a thorough analysis of the issue, the ACS baseline consumption referred to the indoor temperature of 24°C has been computed for three typical residential buildings built in the South of Italy over different periods. The baseline consumption was used as a reference to estimate the effect of the set point temperature change on the ACS power profile. The results showed that increasing the set-point temperature of ACS by 2°C and 4°C leads to a reduction in electrical consumption, which depends on the thermal load and the position of the flat in the building (ground level, intermediate and upper level). The proposed methodology can support Aggregators to correctly coordinate the resources, maintai the grid security and offer Demand Response (DR) programs tailored properly on the basis of specific consumption profiles.