MOO Reports:
Performance and Comfort in Buildings

Have you ever been on holiday or seen pictures on television of housing in a different part of the world and wondered why it is different to your own house style? Many of these differences can be attributed to climatic variations.

The relationship between architecture and the climate is a complex one. Buildings basically have two functions; firstly, to ensure survival and health against the outside elements, particularly wind, rain, hail and snow; and secondly, to maximise performance and comfort, by regulating temperature and humidity. Both of these functions have the aim to keep the body temperature fairly constant so that dwellers do not experience fevers or hypothermia.

The main focus of this report is on the second of the factors, to maximise performance and comfort. Temperature is one factor which needs to be modified; for instance we cannot sleep if we are too hot or cold. The main way of regulating temperature is by varying what is called the cell membrane, which is what the house is made of externally (in Britain this is mainly bricks and plaster).

One change that can be made to the cell membrane is its colour. In hot climates, houses are painted white so that radiation is reflected and not absorbed. This means that the temperature inside the building is lowered.

The shape of the membrane is also important. Horizontal surfaces cool much more quickly than sloping surfaces. This means that in hot climates, where rainfall is low, roofing is normally flat. Conversely, in cool climates, the building will be made as round and aerodynamic as possible to avoid heat loss, for example an igloo.

Thickness of cell membrane is important. In hot arid environments, cell membrane is made as thick as possible so that the pulse of heat is subjected to a time lag. This means that the room warms up at night and leaves the room cooler during the day. In addition, in arid environments very few windows are included as little ventilation is needed and windows have much shorter time lags. An example of such a building might be found in the Middle East.

If the climate is hot and humid, then there are different requirements. Ventilation should be maximised so that the house does not become too sticky. This means that the membrane is kept thin, so that heat can escape, and large windows are incorporated so that ventilation can be maximised. An example of such a building is a Malay timber house.

This idea can also be taken one step further with the idea of compound housing, again used in hot climates. The living quarters, normally downstairs have a thick membrane and few windows, so that it is cool during the day and warm at night (when people are not in it). The sleeping quarters have a thin membrane so that the room is cooled at night as people sleep.  The sleeping quarters get very hot during the day, whilst people are not in there. Of course, there are problems if you become nocturnal....

This MOO report has illustrated some of the differences in housing worldwide. Watch out for the second in the series when the issue of performance and health regulation by housing is looked at.



. 1999-2003 Justin Taylor / John Dray

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