Buildings Guide


Key Message

Choosing an optimal site as well as modifying the microclimate around a building can reduce the energy load of a building significantly. In warm climates planting 1-3 properly placed trees per house, can reduce the required cooling energy by up to 50%. In cool climates, ‘windbreaks’ that shield cold winter winds, can produce higher temperatures of up to 3.3 K in the protected area, thus reducing the heating load. The use of shade trees and light coloured roofing material, as well as high-albedo pavement, will also indirectly reduce cooling loads, by reducing the ambient air temperature.

Dorer, et al., (2013) have conducted experiments to study effect of street canyon on annual space cooling demand and concluded that the dimensions of the street canyons severely impact the latter. The annual space cooling demand is increased by about 6 times compared to a stand-alone building. Moreover, when to dynamic heat transfer coefficients and heat island effect have been taken into consideration due to micro climatic effect, the space cooling demand in further increased by about 9 times compared to a stand alone building.


Climate affects the interior thermal conditions of a building both directly and indirectly. Climate elements that influence energy consumption of buildings are air temperature, radiation (long wave and short wave), wind speed, relative humidity, sky conditions and air movement (Esiyok, 2006). Care must be taken when planning a building to take the climatic conditions into account and the effect these have on the building. Careful planning must be made to reduce the negative effects of climate on building energy consumption. However at the same time with careful planning climatic and prevailing site conditions can often be put to effect to maintain and improving thermal conditions in the building interior.

Factors such as vegetation cover, colour of the surfaces, density of the built environment etc. in any given surroundings effect the micro-climate of the place. The likely impacts are increase or decrease in temperature, humidity, wind velocity, radiation etc. compared to the recordings at the meteorological station. A study conducted by Peng & Jim (2013) shows that Green roof installation on a community scale not only provided cooling effect within the building, but resulted in the reduction of pedestrian-level air temperature by 0-4 - 1-7 °C. It also helps in reducing the heat stress during peak season.


Site and micro-climate
The choice of location for buildings plays an important role in their energy consumption for cooling and heating. In most cases the location of the building site is determined by existing urban structures or master plans. In the case of new developments, however, the location of the buildings should be considered. Depending on the desired effect, the location can supplement the cooling or heating requirements of the building. This could be through use of terrain or natural features to shelter or expose the building for example from solar exposure or the cooling effect from the prevailing winds. Overall considerations of urban sprawl, generation of energy intensive traffic and transportation, and the redevelopment of city centres should, however, take priority in this matter.

Form and Orientation
Buildings in all climate zones should always face the equator, i.e. they must be designed along the East-West axis with the larger façades thus facing south and north. In cool climates the building form must be very compact in order to reduce the heat loss through the building envelope. In temperate zones the form can be slightly more elongated in order to increase the solar gains through the equator-oriented façade. In hot and arid climates, the building form should again, be more compact due to the extreme differences in temperature between night and day. In hot and humid climates, there are two distinctly different approaches, depending on the cooling concept chosen. When designing for a fully naturally ventilated building without air-conditioning, the right approach is a spread-out form with good potential for cross ventilation. When designing a building with air-conditioning, the building must be much more compact in order to reduce the heat transfer through the envelope. There is also the possibility to design ‘hybrid’ buildings, which make use of both air-conditioning as well as natural ventilation, either in different zones of the building, or at different times.


While site (selection) and microclimate are largely predetermined with little scope for improvements, form and orientation can be optimized to a large extent to aid passive building techniques. Though many passive techniques are interrelated to each other they can be sub grouped as described below for the purpose of understanding.

Site and micro-climate
Within (macro) climatic regions local variations can result. These local variations in climate, on a small scale, are called the microclimate. Topography, soil structure, vegetation and urban forms all affect the microclimate. It can be influenced and modified in such a way that it improves the thermal comfort con-ditions both outside and inside buildings. Planting trees and bushes, installing ‘windbreaks’, ponds and fountains for example can improve these conditions reducing a building’s energy consumption for heat-ing and cooling significantly. Considerations when choosing a site for the building and strategies to improve the microclimate around a building include:

Form and Orientation
Designing the building form and selecting appropriate orientation is the first step in the passive design of buildings. Intelligent planning of building form, geometry and orientation not only meets the functional requirements of the building but also respond to the site, microclimate and the solar movement across the site. This is a prerequisite to further design several passive cooling and heating strategies and also to minimize heating or cooling loads on the building.


  • Johanna Knaak
  • Sriraj Gokarakonda 
  • Christopher Moore


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