Purpose - The prices of old apartments in Taipei have reached record highs, with the market exhibiting a 'the older the building, the higher the price' inverse depreciation phenomenon. Because that real estate value includes not only use value, but also contains redevelopment value. This study examines the redevelopment value affected by redevelopment potential and by intensity of use and regional price levels of real estate parcels.Design/methodology/approach - This study is based on the hedonic price model and adopts a semi-logarithmic regression model to explore the depreciation effect.Findings - The results of this study showed that old buildings in Taipei do exhibit increasing value and thus inverse depreciation. The effect of building age on redevelopment value is that, the higher the expandable floor area ratio, the more intense is the inverse depreciation effect. Moreover, the higher regional price levels are, the more intense the age effect is. The combination of these two factors will have an intensifying effect on inverse depreciation.Originality/value - This study separated redevelopment value from real estate price, adopting a direct approach to explore the building age effect in redevelopment value, not only to avoid possible bias due to confusion inherent in the indirect analysis used in previous studies, but also to further clarify the role of redevelopment value in real estate value.