In modern Dutch dwellings, about 10% of the annual use of primary energy is used for cooling, whereas about 50% of the primary energy is used for heating. With the technology of Phase Change Materials (PCMs) energy savings can be made in both areas. PCMs are materials with a high latent heat capacity which are, by melting and solidifying at a certain temperature, capable of storing and releasing a certain amount of energy. Unlike sensible storage materials, PCMs absorb and release heat at a nearly constant temperature. At hot days the PCMs can store (part of) the excessive heat to form a (temporarily) buffer. The heat is released again when the temperature drops below the melting temperature of the PCM. As a result, people inside a building incorporating PCMs can experience more comfort than in conventional buildings. To measure the possible energy savings, an experimental research facility was set up. In this field set-up, modern Dutch dwellings are simulated by using scaled models with and without PCM in the concrete floors. These models are provided with sensors measuring the inside temperature and the incoming solar irradiation. As a reference, a weather station collects data on the outside temperature, humidity, solar irradiation and wind speed. By comparing these data, tihnefl uence of the PCM¿s becomes apparent. In this proposition paper, a research framework to analyse the influence of PCM will be presented. To provide models, software packages will be assessed. The software package, which must be able to calculate the thermodynamic differential equations dynamically, will visualize the incoming and outgoing energy flows. The results, regarding the effectiveness of PCM, will also be implemented in the computation methodology of the Energy Performance Coefficient (EPC).