Figure 3.15 Buildings ratio relative to climatic context

 In hot-arid climate the the summer optimum is 1:1.26, and as the summer stresses are nearly eight times as large as the winter ones, the optimum plan ratio can be 1:1.3 up to 1:1.6.  In hot humid climate the winter optimal plan ratio is 1:1.7 while the summer optimal ratio is 1:2.69, up to 1:3.

Figure 3.15Buildings ratio relative to climatic context

In larger buildings choosing the optimal orientation and form can be more limited due to plot size, surrounding buildings, as well as the spatial and programmatic organization of the building itself etc. Olgyay lays out general principles for larger buildings, such as:

 In cool climates, the compact forms are preferable with a "back-to-back" buildings plans on the north-south axis due to their relatively dense cubature. The environmental pressure favors higher buildings in this type of climate.  In the temperate zone there is a freedom in form due to the more favorable climate conditions, and the buildings elongated to the east-west axis are preferable.  In the hot-arid zone, massive shapes are more advantageous, with cubical form or elongated towards the east-west axis. High buildings are preferable.  In the hot-humid zone the buildings should be elongate to the east-west axis.

Orientation and sun exposure

The solar insolation intensity vary according to the buildings orientation. In Figure below two positions of the building are shown. In the south position, facade A, faced south, has the largest solar insolation in March and October which are beneficial periods for passive solar warming of the interior, as the heating season ends and begins, respectively. During the summer the insolation decreases on the south facade which lowers the energy demand for cooling. Thus the facade has optimal orientation towards south or up to 20° to the east.