SUNLIGHT has been used for thousands of years to heat or cool buildings. Originally a matter of mere survival, it has since become an expression of the human need to harness solar energy and create a better world for themselves. Historical records suggest the formidable powers of the sun, both in its cruelty and generosity, have been the object of study of both philosophers and inventors. Primitive shelters in tropical regions still bear the mark of this. The purpose was either to create shade, direct cooling winds into the building, remove humidity or cool heavy constructions.

The designs and materials used in the buildings were deeply rooted in local climate and were crucial for the standard of comfort. This is evident in the concern Socrates showed in it: "In dwellings with south-facing facades, the low winter sun shines far into the interior of the building. But in summer, the path of the sun is above our heads and above the roof, so that there is shade inside. We ought, therefore, to build the south sides more open to let in the winter rays. The north side should be more closed to shut out the cold winter winds."

The Pueblo Indians in southwest USA built thick earth walls and roofs in such a way that the heat of the sun was transferred to the walls and roofs. When night fell and the cold desert air cooled the surroundings, the heat trapped in the walls and the roof permeated inside and maintained a pleasant warmth.

Interestingly, we observe shades of Socrates in the ceremonial buildings of the Pueblo Indians. Their buildings, too, were oriented to the south to let in as much of the low winter sun as possible.

History is full of such climate-sensitive buildings. In recent times, they can be found in saltbox houses in New England, USA.

But, like the technological history of solar energy, the history of such architecture is a tragic example of how faith in cheap fossil fuels suddenly led to the abandonment of all inherited knowledge about climatically-adapted building habits.