Buildings should all face certain directions, depending on their location in the world – in the Southern Hemisphere, they should ideally face north. The reason for this is to provide residents with comfortable living conditions throughout the year. This is done by optimising on the sun’s warmth during winter, which shines from a more northern point in the sky.
In hot and dry climates, which generally occur at latitudes between 0 and 30 degrees, the daytime temperatures in summer can peak above 45 degrees Celsius. Tanzania falls within these latitudes, but is located just south of the equator. These climates do not receive excessive rainfall during the year and the humidity can be quite low.
The buildings in these climatic zones should be orientated so that they receive as much sunlight in winter and as little sunlight in summer as possible. The ideal orientation is north-facing. This means that the main windows should face in a northerly direction in order to allow light and warmth into the house during the cold of the winter.
In summer, the sun is further south. This means that no sunlight will enter the main windows and doors, keeping the building cooler during the heat of the day. The building orientation depends on the architect and building contractors, but it can have a big impact on the internal temperatures of the rooms, throughout the year.
Typical features of buildings in hot and dry climates
1. Building layout – Different rooms should occupy different positions in a house. Long walls with windows should face north to maximise solar exposure during winter. The kitchen should be placed on the downwind, or leeward, side of a house. This will prevent hot air and the smell from the kitchen blowing through the house. Bedrooms can be located centrally to keep them insulated from outside temperatures.
2. Windows and openings in the walls – Large windows and openings in the walls should face north and west. This will allow the warmth from the sun to enter a building in winter and at sunset. During summer, the sun won’t shine through north-facing windows, but it will still shine through west-facing windows at the end of the day, providing a bit of warmth for the night.
3. Layout and building of walls – The thickness of the wall plays a big role in heat insulation. Buildings in hot and dry climates should have thick outer walls to act as an insulating barrier, keeping the house cool in summer and warm in winter. Houses should be painted light colours in hot climates to reflect the sun’s heat. The paint should also be smooth and glossy to further insulate the building.
4. Layout of the roof – The roof of a house in a hot climate should be well-insulated and slope in a windward direction. This will allow the roof to cool as the wind blows directly over it. The insulation will also stop the heat from the roof entering the house during hot summers. Ideally, roofs should be tiled with concrete or clay tiling, not tin. Tin roofs can get extremely hot during summer, whereas concrete is a better heat reflector and insulator; concrete tiles will keep a house cooler in the summer and warmer in the winter.
5. Vegetation around a house – The trees and bushes around a house play a big part in its thermal properties. Large trees cast shade over windows, walls and roofs. These should be planted on the south side of the house to provide maximum shade during summer. Make sure that the roots do not grow into the building’s foundations.
In hot and dry climates, such as Tanzania, building orientation is important. It determines how warm a home can be in winter and how cool it can stay in summer. Architects and contractors should pay attention to the orientation of a building when designing and constructing it.
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