Street Widths and Orientation

The amount of direct radiation received on the street (and to an extent, on the lower floors) is determined by the street width. The orientation affects the time of the day when the radiation is received. Modulating the street width and orientation can very effectively control solar radiation.

The solar altitude and azimuth determines the position of the sun at all times. The street width to building height ratio determines the altitude up to which solar radiation can be cut off. Similarly, the street orientation determines the azimuth up to which solar radiation can be cut off. As a result they can be used very effectively to minimize or maximize heat gain. Street width to building height ratio also affects the daylight received.

In hot-dry climates, the prime need is to minimize heat gain. This could be achieved by cutting off the sun. Small street width to building height ratio ensures narrow streets and, thereby, shading. In particular, streets running north south should be narrow. This would enable mutual shading from the horizontal morning and evening sun. East-west streets are avoidable as they allow uncomfortably low sun in the mornings and evenings. However, if unavoidable, they too should be narrow. The exact orientation of streets can be determined by considering the solar geometry in combination with building heights. This will enable us to orient the streets such that comfortably low sun is shielded off by the buildings.


In cold climates, wide streets, especially the east-west streets allow buildings to receive the south sun. However, the need here is not just to gain heat but also conserver that which is received. So settlements should be compactly planned. North-south streets should be narrow. Low building heights are preferred. This would enable heat gain from the roof to be maximized. However, heat loss also has to be minimized.


In warm-humid climates the primary need is for air movement. Streets, should therefore, be oriented to utilize the natural wind patterns.