The amount of energy used to heat and cool buildings is a significant concern that impacts on issues from national policies to personal desires of cost and comfort. The key to achieving optimum performance is the control of the energy flows in the building and its environment. Such control is secured through monitoring and altering the driving sources to maintain the desired thermal and air quality conditions in a space while external and internal conditions (e.g. seasonal climate, indoor heat gains, pollutants etc.) change over time. Thermal modelling tools are essential for the energy efficient design of buildings and their associated control systems. They are used for a wide range of tasks including policy making, cost analysis and comfort evaluation. This paper reviews the evolution of zonal airflow and thermal models, principally for single room analysis, used to design and control heating and cooling in the built environment. Insight is offered into the problems of modelling building energy flows and the results of various models are compared with experimental measurement. Finally, current state-of-the-art modelling is reviewed with emphasis on the development of models that designers and engineers can use to obtain a more accurate evaluation of building energy flows.