ASHOK Gadgil, Arthur Rosenfeld and others at the University of California at Berkeley have proposed "low-E (emissivity)" windows with coatings to reduce heat transfers, can be a viable option for developing countries because they will save energy and reduce peak-hour demands.

But the windows proposed by Gadgil and company are not as "bright" as the switchable ones and are established fixtures in more than 25 per cent of the new buildings in USA. Low-E windows are double-glazed, argon-filled sealed windows and the coatings help filter out the hotter rays of the sun.

Saving costs
According to the scientists, electricity consumption by commercial buildings in countries such as Indonesia, Malaysia and Thailand, is more than 30 per cent of the total electricity generated in that region. Air-conditioning accounts for a large fraction of this and cost savings from reductions in the air-conditioning equipment capacity as a result of using low-E windows, exceed the greater price of these windows.

The study, however, points out that introducing the advanced windows technology will be difficult in developing countries such as India, because of the high initial costs, lack of indigenous production, and uneven competition with subsidised energy.

While low-E windows may be appropriate for the developing world, the future in the developed world belongs to the switchable smart windows, believes Lawrence Berkeley Laboratory's Stephen Selkowitz.