The use of computerized simulation often begins and ends in the construction document phase of a building’s design. However, the use of simulation can be beneficially extended both earlier and later in the life of the building. With an eye toward earlier implementation, this research briefly investigates the role of architects as both providers and consumers of energy (and daylight) simulation.  In addition, this research investigates potential uses of design-phase energy simulation post-occupancy, including building benchmarking and on-going commissioning.  The presentation explores particular real-world barriers to these practices, identifies possible solutions, and proposes future research to increase the usefulness of energy models for the building owners who commission them.