The Bottle Light

bottle light refractionSometimes, a simple idea can be immensely powerful. Maybe the bottle light is not something that makes a huge difference to your life or mine but, for those who live in shanties with little or no electricity, this is a godsend.

screencap from a BBC featureEssentially, one fills a used, transparent, plastic bottle with water and a little bleach (to prevent algae) and sticks it into a hole in the roof.  That’s it. Oh, and don’t forget to seal the edges of the hole.

The light that it produces is equivalent to a 50 or 60W bulb. Of course it won’t work at night but when you think of the dark homes that some of our less fortunate citizens live in, this can—at the very least—brighten up their day.

BBC News Magazine
A Liter of Light

The Gaming of LEED Ratings

We all know that the LEED system can be gamed but that it could be turned so completely on its head was news to me.

greenwashThe Bank of America building at One, Bryant Park, New York has a LEED Platinum rating and was the first skyscraper to ever be awarded this but now, it turns out, it uses more energy per square foot than other building of similar size in all of Manhattan. Wow.

It was hailed as a major achievement by none other than Al Gore who set up his offices there. The basic problem is that LEED is largely based on computerised energy models and “intent”. This makes it open to abuse because it’s easy to purportedly intend something at the design stage and then change the goalposts later on.

Coincidentally, just this morning, I was speaking to a couple of marketing guys who were trying to convince me to attend a “green summit” next month and one of their selling points was LEED. I declined, telling them exactly what I thought of LEED but I wish I’d seen this article just a few hours earlier:

Bank of America Tower and the LEED Ratings Racket via: ArchRecord

Visit to ecobuild India 2013

ecobuild 2013Yesterday was my day to visit Bombay Exhibition Centre at Goregaon for this year’s ecobuild India 2013.

I was a bit surprised to see some of the participating vendors because there was nothing remotely connected to sustainable architecture in their products.  Others, however, showcased more appropriate stuff.

Was disgusted by a company–which shall remain unnamed–that was promoting artificial thatch imported all the way from Thailand. Can greenwashing get more brazen than this?

On a positive note, I was impressed by products from Corvi and K-lite — coincidentally both are manufacturers of LED lights.  The former have a limited catalogue but all their fittings are dimmable with standard dimmers which is a major plus point in my book.

The show wasn’t very large but I presume it will grow over the years. I just think they should vet the products or else the show, as a whole, will soon lose credibility.

Glaring mistakes

conventional v/s curtain wall

In hot climates, the overall energy usage rises as you increase the glazed area. Curtain walls, therefore, are highly inappropriate.

I have ranted about glass façades for a long time and this editorial by Sunita Narain of DTE has inspired me to add a couple of paragraphs to the original one.  Among other things, she has written about a recent study by IIT-Delhi which found that, in our hot climate, the manufacturers’ claims of special coated glass or double/triple glazing being able to reduce heat gain are rather hollow.

One of the other specious arguments put forth in an attempt to portray glass curtain walls as green systems is to say that it reduces the electricity consumed for lighting. This is a half-truth. Leave aside the uncomfortable glare that people working inside such buildings have to put up with, let us make a simple comparison.

Consider a 10m² conventionally designed space. Assuming that we don’t take passive cooling techniques into account, the air-conditioning load will be in the region of 3,500W (1 ton).  Lighting the same space, on the other hand, will need just 50W with fluorescents or 40W if we’re using LED fittings.

Now, imagine a similar sized curtain-walled space. The maximum saving that can be achieved by reducing lighting is a puny 50W. However–and this is the big problem–air-conditioning requirements will probably have risen to a whopping 5,000W.  Even with all the specially coated and multi-layered of glass in the world, the total requirement is unlikely to be anything less than 4,500W.

So yes, we may not use as much electricity for lighting but, I’m afraid, the energy usage for cooling will go right through the roof and no amount of marketing spin can get around this simple fact.

Building walls with the rat trap bond

Just in case I’ve got you visualising rodents scurrying about where they’re not wanted, ease your mind; the rat trap bond I’m talking about is simply a method of laying bricks when building a wall.  It’s similar to the common “Flemish” bond but instead of putting the bricks on their face, they are placed on their edges. This leads to cost savings because less bricks and cement are needed which, in turn, reduces the embodied energy of the wall.

The Rat Trap Bond

Bricks are laid on edge to create an air gap between two layers

Laurie Baker took every opportunity to try and make people realise the value of this method but, by and large, the 20-25% saving in brick doesn’t seem to have been appealing enough.  The rat trap method of construction was popular in England until the start of the 20th century but sustained lobbying by the brick-making industry convinced people that that it was not strong enough to build load-bearing walls.

That is rubbish of course; it’s strong enough for one and two storey buildings as has been proven over and over again by Laurie Baker’s lasting work. But masons too are not usually happy about adopting this system and come up with all sorts of excuses to try and avoid it. I have to admit that, till date, I have not pushed hard enough against their inertia but now I’ve just got one more reason to do so.

For the ShKo bungalow at Karjat, I plan to use the rat trap walls and wanted to know just how much difference they would make thermally. Nobody seems to have done a calculation of the difference — at least there was none that I could find. So, armed with some data from thermal calc and the energy evaluation component of ArchiCAD, I tried to do just that.

Taking just a simple 3m x 3m structure with no openings, I ran a calculation for both types of wall. Result: average U-value of the structure’s outer shell dropped about 15% compared to conventional walls and the energy required for cooling also fell by about 8%. The difference was exaggerated because the model had good roof overhangs to shade the walls.

Still, when you think about it, 8% is nothing to scoff at.  In addition, the embodied energy is reduced quite dramatically and, of course, Laurie Baker’s original reason for using the rat-trap bond still stands — the wall is simply cheaper to build.

Now, I just have to go and steam-roll the masons into learning a new technique.

ShKo Bungalow at Karjat

The design for the ShKo bungalow at Karjat has finally been completed. It’s taken a lot longer than most because, apart from the complex slope, there was a severe constraint of building within a small portion of the entire one acre plot — the rest is prone to occasional flooding from the adjoining river.

Like other architectural designs, this too makes maximum use of local materials and of passive cooling.  External stone walls are at least 24″ (60cm) thick and provide a formidable barrier to heat-gain even in a place like Karjat.  Deep verandahs on the South and West don’t allow direct egress of strong sunlight from mid-mornings till evening. And high roofs with openings at upper levels allow constant ventilation to take place.

Rainwater harvested from the roof will be collected in the basement that is automatically formed by the sloping land. It will also be used to flood the pool which will not, hopefully, have any chemicals used to disinfect it. The current plan is to do natural filtration but the eventual system will depend on getting a reliable and qualified consultant to carry this out.

View from the gate

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The entrance is set within a recess adjoining the car-port. Deep roof overhangs protect most walls from direct heat-gain. All external walls are at least 24" (60cm) thick and made of local stone to keep the interiors cool even in summer.

Comparing LED & CFL Fittings

For the MChi interior site in Bombay (Mumbai), I found some really nice LED light fittings but they are more than three times the cost of identical CFL fittings. Now we all know that LEDs consume very little electricity  and they have an extremely long life but I wanted hard numbers to convince my clients – after all, they are the ones paying for everything.

It didn’t take long… At the light shop, it was pretty obvious that the 18W LED fitting threw as much light as an identical one housing 36W of CFLs.  Frankly I was a little surprised by the 1:2 power consumption ratio because I always assumed it was more like 2:3. However, LED technology is making such rapid strides that yesterday’s facts are already redundant. Putting all the costs into a spreadsheet immediately produced a very compelling argument in favour of the former.

An Example of Total Cost of Ownership - LED v/s CFL

While the life of an LED bulb is in the region of 50,000 hours, the calculation over such a long period (while in favour of LEDs) is rather unfair because even at 5 hours per day, that means 27 years.  Instead, I’m working with 30,000 hours which represents a more realistic 16 years.

Even accounting for the fact that the LED driver (an electronic device that regulates the power that LEDs receive) doesn’t have a 50,000 hour life, the calculation still showed a huge saving.

The calculations here are not likely to remain valid for long because the cost of power is sure to rise even further and that of LEDs can only go downwards.

And here are some images of what the house is going to look like when complete.

View of Living Room

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High-Rises and Sustainability

SkyscrapersReading an article in Architecture Week about the impact that urban towers have on the natural environment, got me sitting on one of my pet hobby-horses.

I have never been convinced by arguments that high-rises are better and more sustainable than low-to-medium height buildings. I suppose some people get a kick out of defying gravity by erecting very tall structures but that, to my mind, is pure hubris.  Even if we dismiss the recently publicised link between the building of skyscrapers and a bubble economy, I still say it doesn’t make sense — purely from the sustainability point of view.

It may sound anachronistic but the fact remains that living high above the ground makes you lose touch with it.

One of the favourite arguments by proponents of tall buildings is, that they free up open space by reducing the physical footprint of built-up areas  However, at least in the Indian urban context, this is a fantasy that all but the most delusional will reject. In Bombay (Mumbai) where I live and work, every single patch of land is covered to the maximum. What little is left open–because it is mandatory–soon gets swallowed up by parking.  There may be a token play area, swimming pool or jogging track, but blank expanses of unpaved space where children can play freely, are conspicuous by their absence.

The second argument in the urban context is: as land is scarce and expensive, having high-rises propels affordable housing. Bunkum! You don’t need to look beyond Tokyo, Singapore and Hong Kong to realise that cities with the most high-rises also have the most expensive property in the world.

The other favourite argument of the tall-buildings-are-good school of thought is that they reduce energy usage in comparison to low-rise sprawl. Unfortunately, data shows that the opposite is the case..While the energy cost of transportation will certainly be higher if people live in far-flung areas, the overall energy footprint of a high-rise dweller is far greater.

Tall buildings–especially those that have large parts clad in glass–need much greater cooling in a tropical climate like ours.

Why is this?

High-rises have a huge amount of embodied energy in their construction and materials. Adding to that, the energy cost for “lifting” people and water against gravity is constant and very high.  This more than compensates for the additional carbon footprint that a suburban dweller uses — especially if the suburban dweller is able to rely on public transport for the daily commute. Ninety five percent of this city’s citizens do exactly that.

And what about quality of life? Given a choice, families–especially those with young children–would invariably prefer a place where the young ones can grow up with enough place to play. But that is altogether another story.

Further Reading:


PSah Factory

For most projects, I not only design, but also execute the work. For this one, though, because of distance, I only did the former.

The clients, manufacturers of packaging material in Cuttack, Orissa, wanted to construct a factory that was not just functional but, to the greatest extent possible, a green building in all respects. The product they make is hardly environmentally friendly, so it was somewhat ironic, but they had a genuine desire to make a change for the better so I agreed to take the assignment.

Design Principles

Initial concept

The initial conceptual structure had clerestory windows on the north and curved roofs to take maximum advantage of prevailing winds

Initially, the structure was to be of a single story only so, had that remained the case, the factory might just have looked like a variation on a theme with north-light roof trusses and curved metal roofs instead of straight ones.

Instead, and as luck would have it, the clients decided that they needed at least one additional floor to house the lighter machinery. Land in this area–alongside the Mahanadi river–is expensive and it would do them no good to scatter multiple structures all over the 2 acre plot. That posed a problem for the design as the clerestory windows would be of no use to the lower floor — either for light or ventilation.

View of Factory from the North-West

North West corner of the factory. This was the final design based on which the factory was actually built. You will notice that windows facing North are twice as large as those pointing West.

So, to allow for the clerestory windows to be used by both floors, I thought to turn them sideways. Back at the drawing board, I realised that only allowing windows on the North and East would mean the interiors of the factory would be dark for much of the day — not to mention that natural ventilation would be nil. On the other hand, too much light from the South or West was not desirable and neither was a draft that could carry in dust particles.

So I reverted to an undulating form–a double wave form in fact–that not only softens the factory outline but also works better for ventilation. Here the smaller waves face the South and West and the bigger ones face the North and East.

View of the factory interior

A rendering of the factory interior shows how the light enters indirectly

Now, when light enters, it reflects off the inner side of the baffle walls. Any heat that is generated remains in the immediate vicinity of the windows. Additionally, the upper of the two windows is bottom-hung to allow hot air to easily escape.

Between successive waves in the baffle walls, horizontal awnings protect the more conventional windows from the sun during the hottest times of the day.  In fact, sun-studies were carried out to ensure that the sun’s rays almost never directly reach the building’s interiors between 10:00am & 3:00pm.


Factory under construction

A view of the factory under construction shows the flyash bricks used for the walls.

Being a large structure which needs to take heavy loading, the framework and slabs had necessarily to be in RCC — a material that I avoid using when it is not required.

All the walls, including those of the baffles were from flyash brick and plastered only where necessary. Initially, we wanted to use the local laterite but that worked out much too expensive.

Some more photos of the construction

SVAGRIHA – a simplified version of the GRIHA Green Rating System

They’re calling it “Small, Versatile, Affordable” GRIHA – a less complicated green rating system for projects less than 2500 sqm. in area.   Quoting from the email they sent me:

ADaRSH (Association for Development & Research of Sustainable Habitats) is pleased to announce the launch of

Small Versatile Affordable Green Rating for Integrated Habitat Assessment

A Rating system for small homes, offices and commercial buildings with built-up area less than 2500sqm

SVAGRIHA is a significantly simplified, faster, easier and more affordable rating system and will eventually function as a design-cum-rating tool. It was required that attention be paid to smaller buildings in India which although have small individual environmental footprints but their cumulative effect is far bigger. SVAGRIHA has been designed as an extension of GRIHA and has been specifically developed for projects with built-up area less than 2500sqm. SVAGRIHA can help in design and evaluation of individual residences, small offices and commercial buildings. The rating comprises of only 14 criteria (instead of 34 of GRIHA) and the interface comprises of simplified calculators. These calculators can be filled using information from construction drawings like areas and quantities of materials. This can be done easily by the architect of the project. Once completed, the tool will tell the consultant the number of points that they are able to achieve in that particular criterion and provide recommendations for any improvements in order to improve the environmental performance of the building.

Process of SVAGRIHA Rating

  • Registration of project with ADaRSH
  • Submission of completed calculators, drawings and other documents as required (quantity estimates) to ADaRSH
  • Assessment/Review as per SVAGRIHA
  • Site Visit and due diligence check post construction (mandatory)
  • Evaluation by GRIHA certified Evaluator
  • Award of Rating.

Note: The site audit to check compliance will be done once the project is complete and all equipment to be verified are installed.

For more information please visit

GRIHA is the national green rating system for India developed by TERI and the Indian Government. I’ve always felt that GRIHA is far more suitable for us than (the more popular & better known) LEED rating system.

SVAGRIHA has just 14 criteria compared to GRIHA’s 34 and can act as a good checklist at the design stage.

SVAGRIHA CriteriaSVAGRIHA point groupsLooking at the point groups, I’m happy to note the weight given to Energy and Water conservation. At the same time, to achieve a rating, the design must achieve minimum standards in all categories. So while they say that 25 our of 50 points will give you a one star rating, adding up all the minimums means you actually need at least 28 points.  And finally, the table below shows the star rating that can be achieved.