As part of a thermal retrofitting process of existing housing, energy and thermal performance is normally predicted by dynamic simulation that supposes standardized patterns of building use, without considering the key role of the users in building's energy consumption. This represents a weakness in how the evaluation and design of retrofitting projects is structured, as integrally determining factors in thermal and energy performance are not considered. Integrated evaluations of the homes being improved will help to choose effective and objective guidelines. This work proposes a more objective and holistic evaluation that uses varied and compared techniques, involving the user in post-occupancy evaluation so that they provide feedback for the improvement's design. The integrated diagnosis comprises numerical calculations, onsite measurements, energy simulations and an estimation of the user's perception, with the goal of showing the different results obtained through the different methods. The study shows great differences in what users perceive and expect with the suggestions for thermal improvement obtained from the simulation. It is concluded that, to attain a higher user satisfaction and a better energy performance of the building, thermal improvement strategies must be defined not solely based on standards or previous cases but must consider the expectations of the inhabitants and including experimentally measured values of certain physical-construction properties to calibrate the dynamic simulations.