This research data collection and statistical analysis has explored how people move inside office buildings, where to and why. In real, practical situations, however, office design can be infinitely varied, which raises two questions: (i) is it possible to extract general laws about human movement in an office environment? and (ii) can we make them sufficiently precise and quantitative to be useful in practice e.g. as a tool in office layout design? To achieve this in full generality would certainly require an entire research program and is beyond the scope of this book. However, here we shall take an initial step in this direction by proposing a quantitative model that captures the main insights of the movement research data in the form of a set of equations, in order to allow us to apply these insights in an unambiguous way to new layouts. In particular, the purpose of this model is to have a practical way of estimating the total energy expenditure per person per day in a given office layout.