Systematic computer simulations and energy performance studies are conducted for a typical residential building and prevalent conditions in the Gulf region. The studies systematically deal with variations of the main geometrical parameters of the building envelope, comprising plan proportion, orientation, glazing allocation and obstruction. Comparative evaluations and sensitivity analyses expose the effects of these variables and define their relative contributions to prime energy-performance indicators. The combined effectiveness and potentials of the parameters compensate for their limited individual contributions to warrant their practical consideration for passive architectural and urban design application.