There are two opportunity costs for vacant buildings：（i） value of the building depreciates without a usage of the building and （ii） in case service life of the building has already passed, demolition to utilize the land is delayed. A framework to estimate these costs is proposed, using a depreciation curve and data on household-owned vacant detached houses for entire Japan from Housing and Land Survey. The cost for a year is estimated as 86 billion JPY and the cumulative cost to date for current vacant houses is estimated as 651 billion JPY, mainly from the building depreciation channel at an early stage of a building life.
