It is difficult to gauge running costs after tenants have moved in with condominiums. However, with general consumables—automobiles, for example, fuel economy is a criterion in selecting the product, and ties up with ecology. This concept of clarifying running costs was adopted with the following for this condominium block: 1. Energy-saving heating and air-conditioning; 2. Other utility costs; 3. Maintenance costs (management, repairs, car parking, property tax, local taxes, etc.). This provides a new method of comparing each condo with residential houses and privately-owned condos.