Modern heritage, particularly post-war social housing estates, is struggling with negative perceptions. Accordingly, this research aims to contribute to a better understanding of the heritage significance of post-war housing estates in general and the Western Garden Cities – a post-war neighborhood in Amsterdam – in particular. A review of the limited body of literature on the heritage significance of modern and post-war housing estates was performed. A significance assessment was conducted on a sample of representative case studies by using expert interviews for data collection. The experts assigned significance levels to attributes based on whether or not they need to be preserved during a sustainable refurbishment. The highest-valued attributes are parcellation, balconies, and semi-public green spaces. The most negative value was assigned to the application of external insulation, replacement of the window frames by PVC-U, and closed character of the façades on the ground floor level. The lack of heritage recognition at the lower scale level may either be due to the important details already being lost or details not yet consistently being recognized as the architecture and buildings are understudied in comparison with the urban qualities of post-war heritage.