Glass façades, seen as signs of modernity & progress, are inappropriate for our climate.
Unfortunately, there is a strong trend in India these days towards designing building with glass curtain walls. These are seen as making a break from the bad old days when we were perennially short of power and couldn’t afford to run air-conditioning to keep ourselves cool. Well, I have some news for people with this view — we’re still perennially short of power and cannot afford to run so much air-conditioning.
Our country has a huge shortfall of electric power and that’s not going to change any time soon — at least not unless we suddenly manage to generate power from cold-fusion. In the meanwhile, huge quantities of fossil fuel will continue to be burned thereby exacerbating climate change and making things even worse for everybody and their pet dog.
Glass curtain-wall buildings are inappropriate for our climate for two reasons:
- Having a glass skin means that the inside is subjected to an enhanced greenhouse effect. Glass easily allows short wavelength light like infra-red to pass through. This radiant heat, once it has reflected off objects in the room, is of a longer wavelength which glass blocks. As a result, the internal temperature of the building builds up because the heat has now been trapped.
- This trapped heat has, somehow, to be expelled and – since there is never any significant natural ventilation in a glass building – this calls for massive (and environmentally expensive) air-conditioning. Let us not also forget that living and working in permanently enclosed spaces leads what is known as “sick building syndrome”.
Heat-reducing glass is like a pick-pocket returning your empty wallet.
There are manufacturers of curtain walls who will claim that their products reduce heat build-up by 30%-40%. What they don’t tell you that not having a glass wall in the first place will reduce your heat-gain by twice that amount!
