Coupled energy simulation and computational fluid dynamics were used to model air flow and temperature distributions in buildings, so as to achieve more accurate results than available from either method used alone. Attention was focused on the existence, uniqueness, convergence and stability of the solutions. Both theoretical analysis and numerical experiments were used to verify that the iterations resulted in a correct and converged solution. Three different data coupling methods were assessed, and an improved iterative coupling and control algorithm is proposed. 32 refs.