The impact of the mushy zone parameter ( A mushy ) and thermal properties during the solidification of a commercial paraffin-type PCM in a vertical cylinder under T-history conditions was examined numerically. First, the thermal properties of the paraffin-type PCM and its temperature profile during solidification under T-history conditions were experimentally obtained. The solidification process is simulated by using a numerical model and it was conducted via the commercial CFD code ANSYS FLUENT 2022. R2. The enthalpy‒porosity model was employed by the ANSYS FLUENT for solidification and melting. The accuracy of a simulation is highly sensitive to the software inputs and assumptions. Therefore, selecting the correct values for thermal properties and the mushy constant is essential for achieving precise simulation results. To determine the precise boundary conditions, radiative heat transfer between surfaces is considered. The results indicate that, between the four thermal properties, although increasing the thermal conductivity accelerates the solidification rate, the opposite effect is observed with increasing latent heat, density, and specific heat, as higher values of these properties lead to slower cooling. Moreover, the results highlight that choosing the correct mushy zone parameter is crucial for accurate solidification modeling. Although the impact of   A mush on solidification is generally less pronounced because conductive heat transfer dominates compared with the melting process, for paraffin-type PCMs, a higher   A mush value yields results that better align with experimental data, unlike other PCM materials. Furthermore, the shape and progression of the solidification is influenced by the mushy zone parameter and as A mushy increases, solidification in the bottom layers decreases, with the process becoming more concentrated in the layers closer to the cold wall.