In the last twenty years, the European economy, which has faced two serious crises, nowadays tries to cope with the negative effects of the pandemic that has affected the whole world. Among all these negative effects, the one experienced by the society most is, without a doubt, high and permanent inflation. In this study, inflation inertia was analyzed with linear and non-linear unit root tests for the seven economies which are in non-Eurozone but are members of the European Union. The non-linear unit root tests used take both structural change and regime switching into account. Thanks to these tests, all none-linear dynamics that can be observed in the inflation series were included in the inflation inertia analysis. Moreover, the respective tests were aimed to obtain empirical data more sensitive to the shocks applied in time by Rolling Windows Sample approach. According to the obtained results, while inflation inertia was detected in Bulgaria, Croatia and Czechia, it was found out that Romania and Sweden economies are the ones with the least inflation inertia.