In city buildings the owner is also likely going to be the tenant for all of the building's life; all cost savings from careful asset management and short and long-term efficiency investments will accrue to the city and its taxpayers. In such a circumstance, energy and water efficiency opportunities are almost always justified on a purely economic basis, even without considering the benefits from reducing greenhouse gases, lowering exposure to fuel price volatility, or meeting sustainability goals. Most existing public buildings were not designed to use energy and water efficiently, and even those that are designed well are infrequently managed to capture efficiency opportunities. Energy efficiency and other sustainability opportunities abound in existing buildings, which are in a constant drift toward expensive inefficiency. Many of the opportunities not only reduce operating costs, but improve occupant quality of life, create higher resale value, and improve worker productivity.