This chapter concentrates on the decisions that can be made by the owner. The architect and engineer will have to work within the owner's basic decisions about the location and size of a building but there are many other design concerns of which owners ought to be aware. The chapter presents material which can contribute towards sound decisions at boardroom or committee level, decisions which are vital to the building owner. For building owners it is clear that the climate in their country is an exogenous constraint. The owner-occupier with control over all of the facilities of a building is in a unique position to influence its energy performance. Implicit in the label "developer" is the idea of temporary ownership, during the period of development. The principal message of the chapter is that owners must make themselves aware of building energy performance whether they invest in, occupy, or intend to develop a building.