<p>Residential buildings in Japan have shorter lifespans than those in other countries. Although it is customary for residential buildings to lose value in the real estate market when they exceed their statutory lifetimes, this rapid reconstruction cycle poses an environmental burden. However, increasing the proportion of new housing units built according to strict energy-saving standards could have a positive environmental impact. Research on the economic lifetime of buildings remains insufficient, and the trade-offs between the impact of demand in the national housing stock on CO₂ emissions and the impact of reconstruction on CO₂ emissions throughout an economic lifetime remain under-researched. Therefore, this study investigates the impact of the economic lifetime of Japanese detached wooden residential buildings on CO₂ emissions during the construction and use phases. Specifically, it estimates the economic lifetime of detached wooden residential buildings based on real estate transaction data and assesses the effects of changes in CO₂ emissions during the construction and use phases by altering the average lifetime. The results display that a shorter economic lifetime of residential buildings significantly contributes to increased CO₂ emissions, whereas gradual lifespan increases contribute to a decrease, thereby making a strong case for reassessing the statutory useful life of residential buildings. This study provides evidence that maintaining the economic lifetime of buildings and transitioning to ambitious extensions are crucial aspects of environmental policies</p>