Two methods for reducing weather data are assessed and compared with respect to use for heating calculations. Degree days for calendar months, utility bill periods and without weekends were calculated and compared along with temperature 'bins' of various sizes using the CIBSE Example Weather Year. Wind velocity and solar radiation are also analysed with respect to degree days. Both methods, degree days and the bin method, are found to represent the actual weather conditions adequately for use in heating calculations.

To predict the performance of a naturally ventilated building, estimates of the windinduced surface pressure distribution are needed. In urban environments, where buildings are grouped closely together, these surface pressures will be strongly influenced by the surrounding structures. In addition, the sheltering effect of the surrounding built-up environment can make it more difficult to obtain large enough pressure differences across a building necessary to produce adequate natural ventilation air flow rates.