Abstract The aim of this research is to verify the dynamic performance of 3 envelopes characterised by different traditional wall constructions adopted in temperate climates. In each case the optimal retrofit solution from the point of view of comfort and energy savings is identified. To that end contemporary experimental comparisons were made between 3 buildings which are characteristic of the existing building heritage. They were all constructed between the 1940s and the 1980s adopting envelopes which use different wall constructions to deal with the outdoor climate conditions: capacity (high thermal mass), stratification (different layers and a cavity), and resistance (the use of an insulation layer). Dynamic parametric analyses (EnergyPlus, CFD Fluent) were carried out in order to verify the impact of different retrofit solutions on the buildings studied. The results show that the behaviour of the 3 envelopes differs greatly because they interact in different ways according to climate changes. The use of considerable thicknesses of thermal insulation causes problems of overheating when coupled with high thermal mass, while it is an improvement in the stratified envelopes. The problem of summer discomfort can be resolved by adopting mixed insulation strategies such as a ventilated external insulation layer, which allows the existing envelopes to maintain their dynamic behaviour.