The incandescent bulb is the most common – and one of the least energy-efficient lighting options for brightening a space. Today we have numerous fluorescent type fittings; both, the old tubelight as well as modern compacts which retro-fit into incandescent holders. Light Emitting Diodes – LEDs – are rapidly getting cheaper and have now reached a level of affordability. The ways of lighting an interior or exterior space are numerous. We’ll touch on a few common ones here and see how they compare.

Daylight

Apart from being free, studies have shown that natural light improves productivity and has significant health benefits compared to artificial light. Getting natural light into your home or office is not difficult to do – all it takes is a little planning by the architect at the design stage. Naturally, the designer has to take care of glare and solar heat-gain but once these factors are accounted for, there’s nothing better than sunshine to light up your life.

Unlike in Europe and North America, in peninsular India, light from the north east is the best because it is glare-free. In fact, that’s why vastu stipulates that you put your study in that very corner of your house. Conversely, the south-west is where the glare is worst so it’s better to have shade giving trees to protect you on that side. If you are living in the extreme north of our country, however, where it is really cold in winter, you’d want to open out your southern side and achieve some heat gain. For the rest of us, reflected and indirect light is the best.

The mechanics of daylighting are more complicated and will, time-willing, have a page of their own but suffice to say that every architect should try to achieve adequate lighting without building up heat inside the building.

Tube Lights

Tubelights have been around for a while and, because of the harsh light they gave off in their early days, there are numerous people who hate their very existence. But tubelights are efficient and their colour temperature has improved dramatically in recent times which makes them as comfortable to use, if not more so, than an ordinary bulb.

Tubelights have a long life and their drawback, if any, it is that they require a lot of energy to start up. So much, in fact, that it’s better to leave a tubelight on for 15 minutes than to switch it off and on again during that time.

Compact Fluorescent Lights

CFLs are the new tubelights – they have been squeezed and twisted so that they can replace ordinary bulbs. And they should! CFLs consume just 25% of the energy that a bulb does and are available in “soft white” which is easy on the eyes. Granted, they cost more but the energy saved is more than paid back during it’s life which is 10 times as long as a bulb.

LEDs

LEDs or Light Emitting Diodes are extremely energy efficient and should last for at least 10 years of continuous usage. The drawback is that LEDs are still quite expensive although rapid advances in technology and economies of scale are bringing that barrier down. An LED lamp uses, on average, about 10% of the power that an incandescent would. Add that to its longevity and we have a future winner here.

Efficiency Shootout

Here is a comparison that tells you approximately how much you benefit by installing fluorescent fittings in place of incandescent ones. LEDs have not yet reached mainstream sales so they have been excluded from the table. I am sure that in a short while, though, they’ll be leading the pack.

As you can see, above, the ordinary tubelight is still king. For those who don’t like the harsh light fluorescents generate, please note: they are also available at a colour temperature that closely resembles daylight.

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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:

1. 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.
2. 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.

Glass manufacturers will claim that their specialised 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!

Another specious argument put forth is that using glass walls reduces the usage of electricity for lighting. Again, this is half-truth. Let us, for a moment, leave aside the amount of glare that people working inside such buildings have to put up with.

Consider a 10m² space.  Under normal circumstances, the air-conditioning load would be about 3,500W (or 2,500kW if you’re using a highly efficient HVAC system).  Lighting the same space need just 200W if you’re using incandescent, 50W for fluorescent and even less if you’re using LED fittings.

Now, if the wall even on one side is made of glass, the maximum saving from lighting that can be achieved is 200W. A lot more than this would be lost by the increase in HVAC energy requirements.  Even if expensive special glass is used, I’m afraid no amount of mathematical spin can get around this simple fact.

We can easily save energy and reduce our energy consumption by taking a few simple steps. Most are not too expensive and they pay back fairly quickly.

Solar Hot Water

It’s one of the cheapest and simplest ways to save a huge amount of energy and the payback period is pretty short. The panels to be installed are basic and require very little maintenance. Essentially, the technology consists of nothing but copper pipes which zigzag behind a glass pane and heat the water that runs through them. This water is stored in an insulated tank so that if you wake up at the crack of dawn and try to have a bath, there’ll probably be some warm water for you to use. That’s if you didn’t use it up the previous night.
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Passive Cooling in Tropical Climates

For centuries, until the invention of electricity, architects simply had to take into account the ways of the weather so that the interior of a home or workplace was comfortable for its tenants. In India, it led to the development of the Vastu Shastras – an ancient science that has now been obfuscated into a first class superstition… But that’s another story.
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Energy-Efficient Lighting

The incandescent bulb is the most common – and one of the most wasteful – ways of lighting a space. Today we have numerous fluorescent type fittings; both, the old tubelight as well as modern compacts which retro-fit into incandescent holders. Light Emitting Diodes – LEDs are rapidly getting cheaper and have now reached a level of affordability.
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Star Rated Equipment

India’s Bureau of Energy Efficiency (BEE) has created a system of energy rating for a large range of appliances, equipment and light fixtures. Air-conditioners are, of course, the biggest guzzlers here and, while the initial expense is high if you choose, say, an inverter type, consistent use over time will more than offset the cost. BEE has created an interactive Energy Calculator to tell you how much you would save for different ratings of air conditioners.

Glass Façades in Tropical Climates

In our country today, glass-walled buildings are looked upon as indicative of progress and modernity and an international aesthetic. But the fallout of using such climatically inappropriate designs, is soaring energy consumption and sick-building syndrome.
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What is Sustainability?

“Nature has enough for everybody’s need; not for everybody’s greed.”
- Mahatma Gandhi

Quoting Mohandas Karamchand Gandhi may no longer be fashionable but these words are more relevant today than they’ve ever been.

Every material used in construction comes, eventually, from the earth. For any architect who cares about nature, that is a predicament to be faced every day. I know it is unrealistic to halt the production or extraction of such materials but we should, at the very least, try and minimise their usage.

A simple example: small structures in India are often built with reinforced cement concrete frames when ordinary load-bearing brickwork (which is about 25% cheaper by the way) would be more than satisfactory.

Nature-friendly Architecture & Design

Nature has an enormous ability to repair herself but when we exceed her capacity to do so, this cycle of restoration and renewal is broken.

Sustainable architecture and design takes into consideration all aspects of construction that affect the environment.

There are many factors that go into making a building nature-friendly:

Using Materials Sustainably

A large chunk of a construction’s carbon footprint is determined by the materials used. For small structures, reinforced concrete (RCC) framing is environmentally expensive and thoroughly unnecessary to boot! I’ve found that load-bearing work usually does a better job.
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Better Design & Construction Methods

Better design is not just about aesthetics. It holistically considers architectural design, landscape & plantation, sustainable systems & climatic conditions,. A well designed construction has minimal negative impact on the site and its surroundings.
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Saving Energy

During its life cycle, a building needs an enormous amount of energy for lighting, heating & cooling. A design that makes good use of naturally occurring sunlight & prevailing breezes goes a long way in saving associated costs.
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Saving Water

Economists have pointed out that future wars will be over water which makes this the most important factor in my estimation. Saving, harvesting and recycling water is far easier than it is made out to be and you often don’t need an expert to get it working.
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Waste Disposal

Disposal of solid waste might not be an architect’s area of expertise but we can play a proactive role by designing for composting pits etc.
[under construction]

Impediments

If you compare apples to oranges, you will invariably draw the wrong conclusion.

The biggest deterrent to making clients accept sustainable solutions is, usually, perceived cost. That’s because they almost always compare apples with oranges. For example, if a solar heating system is installed for a project, it will naturally raise the initial cost but, if you calculate how much it saves in the medium to long term, you will find that it doesn’t make sense not to fit it. Essentially, green buildings cost less in the long term.

Even as far as basic construction is concerned, green building costs can be made lower than for typical structures. This was amply demonstrated while building Kaya Kalp where, locally available, low-tech materials and labour were used.