A green facade

By Sunita Narain
Last Updated: Monday 17 August 2015

A green façadeBuilding green is definitely important. But equally important is to know how green is a green building. Take the glitzy, glass-enveloped buildings popping up across the country. It does not matter if you are in the mild but wet and windy climate of Bengaluru or in the extreme hot and dry climate of Gurgaon, glass is the in-thing. I have always wondered how buildings extensively using glass could work in such varied climatic zones, where one needs ventilation. Then, I started reading that glass was green. Buildings liberally using glass were being certified green. How come?

Here the story becomes interesting. The Energy Conservation Building Code (ECBC) has specified prescriptive parameters for constructing an energy-efficient building envelope—the exterior façade of a building. The façade, based on the insulation abilities of the material used for roof and wall construction, will reduce heat loss. It will also reduce energy use if it allows daylight in. It is, therefore, important for any green building to have the right material for its exterior.

But this is not all that ECBC specifies. It goes on to set a wallwindow ratio and fixes the area of the building envelope that can be covered with glass at 60 per cent. This implies that a building can be green and energy-efficient if it is covered by glass. The code then goes on to define the insulation and energy-efficiency specifications of glass that should be used. In this way, double-glazed or triple-glazed glass, which is solar reflective, is preferred as it provides superior thermal erformance. In other words, glass built on certain superior and high specifications can reduce the heat gain of a building. ECBC, thus, endorses the extensive use of glass and promotes high-performance and expensive glass, which is manufactured by a few high-end companies.

Small wonder glass manufacturers are making hay in this sunshine. Saint-Gobain Glass incidentally (or not) is also the founding member of the Indian Green Building Council, promoted by industry association CII. The green code is built for their business to thrive.

This would still have been acceptable had this prescription worked. But first, builders cut corners in the use of expensive reflective material. Glass traps heat, therefore, buildings require more air-conditioning. Energy requirement goes up. Secondly, even when double- or triple-glazed glass is used there is evidence that in India’s extremely hot climate it does not work so well. A recent study by IIT-Delhi in Jodhpur, Delhi and Chennai found that energy use increased with increase in glazed area, irrespective of the glass type used in the building. The conclusion was that the glass curtain wall made of expensive reflective glass did nothing to cut energy costs as compared to ordinary glass ( see ‘Reflections on glass’ ).

We also forget that natural light in India is a glare, unlike in parts of the western world where glass is used to reduce energy use for lighting. So, even if theoretically the use of glass optimises daylight use, it remains a function of how much is used, where and how. For instance, the use of glass—of whatever glazing—in the south and west facades of a building will be bad in terms of thermal transfer. Then, even if you use glazed or tinted glass, where 50 per cent of solar heat gets reflected off the surface, 65 per cent of the visible light is transmitted into the building.

Heat transfer may be reduced but the harsh light filters through. Buildings then need blinds to cut glare, again adding to the use of artificial light and consequently raising energy cost.

What would work better is building protection against direct glare. Go back to the old fashioned methods of providing shades on windows. And do not build tight and sealed buildings, which do not optimise use of natural ventilation and breeze to reduce air-conditioning needs in certain periods of the year. In fact, glass necessitates air-conditioning, and buildings become energy guzzlers. The irony is that these buildings still qualify for a green tag when the air-conditioning system used in glass-cased constructions is more efficient. Build badly and then sugarcoat it, is the principle. Clearly, we need more appropriate and inventive  architecture (see ‘Window to well-being).

What is worse, these codes are being pushed through government and municipal schemes without any evidence that green-certified buildings are actually working. Noida awards a 5 per cent extra floor area for green-certified buildings; MoEF provides fast-track clearance to such buildings. But the two main certificates—LEED and GRIHA, by IGBC and TERI respectively—do not disclose data on the performance of the green buildings after they have been commissioned. So, even though rating agencies say that green-certified buildings save between 30 per cent and 50 per cent of the energy and reduce water consumption by 20-30 per cent, they do not have corroborating data to verify the claim (see ‘A thin green coating’ ).

In this way we make sure that green is not so green. But it is definitely good for business, if not for the planet.


World green building trends

Green building movement in India

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  • Thank you for this article

    Thank you for this article Sunita Narain for highlighting this fact. The folly of glass curtain walls in our climate is something I have ranted about for years and now.

    Most people with common sense easily understand why glass façades are thoroughly inappropriate for our climate. Architects should be even more aware of this fact but, unfortunately, a large number have either been seduced by the so-called "international look" or have fallen prey to false marketing.

    Posted by: Anonymous | 6 years ago | Reply
  • Glass is not green in

    Glass is not green in India.
    As rightly pointed out, too much glass is a bad thing here.
    Very few architects have got green building just right..
    finding the right ones are a challenge..

    Posted by: Anonymous | 6 years ago | Reply
  • The article is very good and

    The article is very good and is the present need of the hour. It is very essential to research and implement the the traditional methods of constructing houses and suitable for present economic and climatic conditions.

    I did research on "Investigations on creating human comfort conditions with the best use of natural ventilation".

    Dr. P. Sanjeeva Rayudu,
    M.Tech., MBA, Ph.D.
    Research Intersests are Energy Efficiency, Energy Conservation and Environment Sustainability

    Posted by: Anonymous | 6 years ago | Reply
  • Nakalchi hain aur nakalchi hi

    Nakalchi hain aur nakalchi hi rahenge, chahe hume Nobel puraskar hi kyon na mil jaye.
    Sunita ji aapne bilkul wajah pharmaya hai. Corruption hame andar tak kha chuki hai. Natural stone marble, jo ki breathe karta hai, ko chor kar har aadmi vitrified tiles pe ja raha hai. Sari windows band kar diye ja rahe hain, to keep the dust out, with the result that house is deprived of natural light and ventilation. It is time Bharat takes over india.


    s k chetal

    Posted by: Anonymous | 6 years ago | Reply
  • Embodied energy of glass and

    Embodied energy of glass and that of aluminium used for the cladding framework is among the highest in building materials.

    Posted by: Anonymous | 6 years ago | Reply
  • An excellent article. I would

    An excellent article. I would request Centre for Science & Environment to come up with a martix on Energy consumption per Sq. M, depending on climate, type of building (Call Centres, Data Centres, offices,Hotels, Hospitals, Shopping Malls, etc), occupancy and Zone.

    As a principle, EPI for all 'Green Rated' buildings should be monitered & recorded on an hourly basis along with monitoring / recording on ambient conditions, occupancy.

    Posted by: Anonymous | 6 years ago | Reply
  • Thanks Sunita for

    Thanks Sunita for highlighting this issue...
    Being an architect myself I understand that architects
    are not learning from the wisdom of our old climatic responsive architecture but simply copying the glass boxes of the western countries and the most non-green buildings are getting a green tag..and some people are simply making money out of this.

    Posted by: Anonymous | 6 years ago | Reply
  • An excellent and timely

    An excellent and timely article. Energy efficiency is just one aspect. This is generally achieved by reduced costs and consumption, depending on design when the constant factor is glass-based facades consented due to commercial forces.
    Yet impacts is another aspect. A limited architect will try to design for style and his customer. But a holistic architect will compute radiations to the environment and trade off between the comfort zone achieved inside vis-a-vis the environmental costs. Green is a challenge and not solution.
    Justification has to be done by accounting for all factors and final ratification by dedicated experts.
    This will spell out where the future of design vs materials balance is achieved.

    Posted by: Anonymous | 6 years ago | Reply
  • A better way to use glass

    A better way to use glass facades is to use ordinary glazed glass with adjustable dual-purpose solar absorptive/reflective louvres behind them. This allows inside temperatures and ventilation to be controlled and maintained within the comfort zone throughout the year with minimal use of power!. Details are provided in my paper 'Solar Active Luvres for Temperature and Ventilation Control in Buildings' presented in an energy conservation seminar several years back.

    Posted by: Anonymous | 6 years ago | Reply
  • Thanks, Sunita. I have had

    Thanks, Sunita. I have had these apprehensions, regarding use of glass in Delhi.Glare is a huge problem. And no escape for heat either. how can architects be so irresponsible?

    Posted by: Anonymous | 6 years ago | Reply
  • Dear Madam, I differ with you

    Dear Madam,
    I differ with you on some of the points discussed here in the above article. These are:-
    1) During Daylight & Shading analysis, both cities with varied climate donÔÇÖt qualify for the same glass specification .Let say for moderate climate in Bengaluru we have higher permissible limit for SHGC in comparison with lower value for Gurgaon-Composite zone (SOLAR HEAT GAIN COFFIECENT-Refers to the increase in temperature in a space, object or structure that results from solar radiation) as per ECBC-2007.As a result, there is major difference when selection of glass is done finally for both the cities mentioned above.
    2) About the WWR-Window wall ratio, which you have discussed about 60%, is the maximum permissible limit which ranges from (1-60)%.So, good energy consultants with their analysis help to achieve maximum daylight in the working space with optimum glass usage.
    3) Double glazed & triple glazed glasses are used when you want to lower the SHGC VALUE. But nowhere, in any codes & standards, it is discussed & mentioned with the promotion of using Double Glazed & Triple Glazed units.
    4) About the research study which you have shared, there are many other aspects like lighting, HVAC & equipmentÔÇÖs efficiency which effect the energy usage of the buildings. Let say by example ,LED lighting with lower(LPD-Lighting power density) value leads to less energy usage & the comparison with increase in glass price canÔÇÖt be compare as usual.

    As, I want to also add here by saying there are many factors & technical analysis which are being considered before going for any glass or technology selection .So ,kindly see the work of major reputed energy consultant which have proved through their ground work & path braking methodology ,with much more desired saving.
    Finally ,I am not in the favour to follow double glass or other technological options available blindly ,but with good work of energy consultants & architects which is practicing by many organization, I am in positive mood to look forward for GREEN technological options which would help to make our PLANET-Green (Coming DAYS !).

    Posted by: Anonymous | 6 years ago | Reply
  • Having been in the green

    Having been in the green building sector let me share my views as well. I agree that ÔÇ£Glass is greenÔÇØ is definitely a market mantra to promote glass which otherwise has been projected as a sinner element in ÔÇ£closed centrally air conditionedÔÇØ buildings. However, effect of glass on heat transmission and energy consumption cannot be seen in isolation, as described in this article, without considering other critical parameters in commercial buildings such as indoor heat gains.

    Glass in buildings has now become more than a functional aspect element and architects cannot be held back from using and designing with materials strictly in the sense of functionality and quantitative benefits of the materials.

    Wall Window Ratio (WWR) is typically 10-20% in residential buildings. Though it varies a lot in commercial buildings depending on the ÔÇ£floor plateÔÇØ design, its depth, daylight requirements etc., it can be pegged at approximately 30-40% to provide acceptable daylight levels and outdoor view. Another important aspect while designing facades in commercial buildings is ÔÇ£Light to Heat Ratio (LHR)ÔÇØ which takes into the account of both visual and thermal properties of glass.

    It should also be noted that in typical commercial office buildings (the likes of call centres, IT parks etc.) the component of internal heat load is very high which makes air conditioning indispensible which in turn results in closed box design of buildings to make them air tight. Factor of heat gain and over all cooling load on the system because of ÔÇ£glassÔÇØ in these buildings is nearly 2-4% at the maximum. Thus, the more the internal heat load and ventilation load on the building the more irrelevant the heat transmission through building fa├ºade becomes. This results in indiscriminate use of glass in buildings where capital cost and running energy costs are negligible for a 30 % WWR building compared to a 60% WWR building. Here glass is considered more a design element than a functional element.

    Other factors such as shading is equally important as WWR which has not been touched upon in this article. As pointed out, designing open buildings with natural ventilation and shades is definitely a good option. However, much information is not available into how to design such ÔÇ£hybridÔÇØ /open buildings in the context of high internal heat loads and not so good outdoor air quality and research is still being done to explore much on this aspect. It is definitely not encouraging to stick to ÔÇ£floor plateÔÇØ and box like designs, but it is the demand of the industry. In order to redesign buildings to adopt more natural solutions, the whole work culture in such environments should be re organized.

    Unlike argued in this article, as of now much have been discussed on the use of glass, its benefits and drawbacks and there is a strong push in the industry especially by the green building consultants to stick to WWR of less than 40%. Factors such as LHR, floor plate design for optimum day lighting, shading, orientation of the building are being well understood and gaining momentum in the industry now. Glass boxes should not be encouraged in India with a predominant hot-dry and hot-humid climate in the growth belt, but any rhetoric should argue in holistic sense of ÔÇ£greenÔÇØ building and also should be pointing out to examples of good practice so that a better contrast can be made.

    Posted by: Anonymous | 6 years ago | Reply
  • Hi Dr. Rayudu, I am also

    Hi Dr. Rayudu,

    I am also pursuing research in the same field. Is it possible for you to share more information on your research?

    Posted by: Anonymous | 6 years ago | Reply
  • This is what happening in

    This is what happening in every sphere. A few group of scientists (favoured group) are also hand in gloves with Industry nexus and so called policy maker experts.
    In due course they will be awarded Padma Shri/Bhusan? But keep exposing all of them. Good luck

    Posted by: Anonymous | 6 years ago | Reply
  • Dear Editor Ms. Sunita

    Dear Editor
    Ms. Sunita Narain,
    Thanks for your article. In fact Codes adopted by neighbouring tropical countries like Hongkong Singapore, even Pakisthan and Srilanka (all adopted energy code earlier than us) do not use such kind prescriptive recommendation as given in ECBC.
    Dr. Seema Gupta (faculty of Architecture IP university) did her Ph.D on this subject under my supervision and we demonstrated that, a controling tool called OTTV used in Codes of Hongkong, Singapore etc is more appropriate than the prescriptive guidelines suggested in ECBC.
    One of our publications is available in Energy and Building is listed below.
    Seema Devgan, A.K.Jain and B.Bhattacharjee. ÔÇ£PREDETERMINED OVERALL THERMAL TRANSFER VALUE COEFFICIENTS FOR COMPOSITE, HOT-DRY AND WARM-HUMID CLIMATESÔÇØ Energy and Buildings. Vol 42, Issue 10, October 2010, pp.1841-1861.
    Thanks and Regards

    Posted by: Anonymous | 6 years ago | Reply
  • Dear Ms. Sunita Narain: Thank

    Dear Ms. Sunita Narain:

    Thank you for your article !

    I have one question. What is green, by the way?

    Japan is one of the most energy efficient countries but it has highest per capita energy consumption. What shall we do? Do we call them green because they are energy efficient or not because higher per capita energy consumption!!

    Green has been evolving as a relative term rather than absolute. When I used to go to school, I had only two choices of pencil and I still remember Natraj and Kamal. Today, my daughter has more than 100 choices. Despite the fact that we have higher level of awareness of green, our resource consumption has been increasing exponentially.

    Do you think concrete or wood or metal or plastic is green, if not glass?

    I am sure you must have studied all criteria they use for certifying building as a green building. There are plenty. Energy consumption is one of them. It is mentioned in the article that energy consumption data is not available for green certified buildings, then how do we say energy consumption is higher and against what we benchmark it?

    Also I remember green leaf award given to industries by CSE. CSE also used numerous yardsticks and not just one.

    In the name of green, we can actually comment on anything. But it is subjective and noisy and becomes GREEN FARCE. Better we collect data, analyze, compare, and benchmark and then decide what is greener? Yes, there can be greener but not green!!!!

    Sincerely yours;

    K D Bhardwaj

    Posted by: Anonymous | 6 years ago | Reply
  • Dear Ashish, I am impressed

    Dear Ashish,

    I am impressed with your analysis of Green building certification systems. Nobody has given detailed explanation like you. Kudos to you.

    However, Kindly look at the picture from an environmental perspective also. Were those old buildings totally covered with glass? Last weekend, I walked past a glass covered building totally reflecting light that was incident on it. I was shocked by the manner in which I got a thermal shock wave. Later when I was walked past an old building with windows, brick construction and lesser glass, it was way cooler than the ambient.

    In India, where the day-ambient temperature is already above 25 degrees C, the reflected glass increases the local temperature thus inducing the formation of UHIs.

    Coming back to the energy efficient appliances and technology, those products have not been designed to Indian conditions. Lobbying from outside the country makes sure their products and technology are marketed in this wholesale market called INDIA. Sad to mention that the architects in our country are not applying their "common sense" on design, economics, environment impacts and energy consumption.

    Sadly speaking, this whole lobbying has now shifted from offshore to an onshore one. The energy consultants, energy auditors, green architects (as they call themselves) have taken the onus of doing this for hefty consultant fees for works that has the worst environmental impact.

    You can argue with me as it might be a case of some random building at a random place. But remember that, small building blocks make a building and accumulation of smaller mistakes is a recipe for a bigger disaster.

    From your justifications, we come to know that you are a full fledged consultant working for a random construction firm. Come out of that, go through the age old "Indian building practices" suited to our climate and bring out the best out of you and for the country. If you don't find any such data, use this opportunity to create a database for the future.

    Finally, do not cringe about criticism of your professional practice. It is more than 90% true as I have worked in a Green building as well as in an energy consultancy. Not any more.

    Hope you take things in the right spirit.

    Posted by: Anonymous | 6 years ago | Reply
  • Dear Vistasp, Thank you for

    Dear Vistasp,

    Thank you for your kind words, we really appreciate that you have been raising voice on the issue. Common sense doesn't seem to be that common these days, but blame cannot solely be placed on architects. Glass industry is doing brilliant job of green washing for creating a massive market for itself. In fact end users are demanding glass buildings from architects. Thus even if a sensible architect wants to keep glass in the façade at its minimum, they are been forced to gloss up their design. Acquired aesthetics are playing havoc functionality of our buildings.


    Posted by: Avikal Somvanshi | 3 years ago | Reply
  • Dear Maya, You are quite

    Dear Maya,

    You are quite right in your observation. Finding a real green building or sincere architects is a really tough challenge. But even more challenging is finding a client who really wants a green building. This is a bitter truth as told by the handful of sensible architects in our network. But, CSE is trying to find these exceptions and document them. You can read our coverage of these rare courageous geniuses of architectural profession in our on-going classroom series.


    Posted by: Avikal Somvanshi | 3 years ago | Reply
  • Dear Dr. Rayudu, Nice to hear

    Dear Dr. Rayudu,

    Nice to hear about your work. It is high time we should start exploring our comfort conditions in Indian context. We would like to read more about your research and investigation on human comfort conditions. Pushing our population to acquire comfort conditions meant for temperate climatic zones can have dire consequences on our already precarious energy and resource scenario. Clock is ticking for us.


    Posted by: Avikal Somvanshi | 3 years ago | Reply
  • Dear Chetal, Your concerns

    Dear Chetal,

    Your concerns are rightly placed. Bharat has the wisdom and experience from which todayÔÇÖs India can learn from more than ever before. But it is a complex exchange which needs to take place because of the drastic lifestyle change, and this is the sticking point in the building debate. Recent policies and codes especially ECBC has taken a easy way out by accepting that urban India will continue this western inspired lifestyle, thus sidelining the debate. ItÔÇÖs time to start opening our windows and look inwards.


    Posted by: Avikal Somvanshi | 3 years ago | Reply
  • Dear Chockalingam, Embodied

    Dear Chockalingam,

    Embodied energy of glass and especially low-e glass is really high. Industry argues that the amount of energy savings achieved by using low-e glass over normal plate glass is good enough to off-set its embodied energy. But the point missed out by most is the high usage of glass in façade increases the overall energy consumption of the building. Measures like low-e glass then bring down these elevated numbers, which even then are greater than the energy consumption of the building which uses much less amount of glass. This needs to discouraged all across the country.


    Posted by: Avikal Somvanshi | 3 years ago | Reply
  • Dear Jaishankar, Nice

    Dear Jaishankar,

    Nice suggestion. In fact we are already working on a similar thing. It would be shared in the public domain in the near future.

    Thank you.


    Posted by: Avikal Somvanshi | 3 years ago | Reply
  • Dear Ujjwala, Really nice to

    Dear Ujjwala,

    Really nice to hear from concerned architects like you. It is true that we need more architects who can see through this alarming trend and raise concerns over the mindless commercialization of the profession. In fact, architects who build houses for peopleÔÇÖs habitation share similar accountability to the society, as professionals like doctors and lawyers.

    Thank you.


    Posted by: Avikal Somvanshi | 3 years ago | Reply
  • Dear Dr. Maydeo, You have

    Dear Dr. Maydeo,

    You have beautifully described the challenge which stares us in the face. We totally agree that ÔÇÿGreen is a challenge and not solutionÔÇÖ. But our undoing is that there is a drought of sensible architects. Further the unprecedented growth of real estate is shrinking the space for holistic development, at an alarming rate. This was one of the principle reasons why energy efficiency code was introduced. Its role was to mandate the ÔÇÿlimitedÔÇÖ architects/developers to dig deeper to design and build something sensible if not great. Sad thing is that the code in its current state gives too much leeway, almost to a point of being unreasonable. We need India specific solutions, copying western models havenÔÇÖt worked for other fields and it will surely not for our buildings. In fact copying west blindly has led to this crisis.

    Thank you.


    Posted by: Avikal Somvanshi | 3 years ago | Reply
  • Dear Mr Arora, Very

    Dear Mr Arora,

    Very interesting technique mentioned by you in the response. We would like you learn more about it. Is it similar to solar chimney? Kindly share your paper with us, it will be appreciated.

    Thank you.


    Posted by: Avikal Somvanshi | 3 years ago | Reply
  • Dear Kalyani, The bigger

    Dear Kalyani,

    The bigger question here is how can be the law makers ignore this? What good are regulations if it allows questionable practice to continue when they are supposedly meant to discourage them.


    Posted by: Avikal Somvanshi | 3 years ago | Reply
  • Dear Ashish, Thank you for

    Dear Ashish,

    Thank you for sharing your observations and differences with us. Let me attempt to clarify some of the points raised by you.

    1) Yes, there is difference in the SHGC standard prescribed by ECBC for Bengaluru and Gurgaon because of the different climatic zone, but there is no difference in the allowed WWR. Both regions have leeway to go up to 60 per cent, which is what we are objecting to. If the SHGC standards can change due to climatic condition, then why a blanket approach for WWR which has a direct relation with energy performance of the building.

    2) Yes, the range of 1-60 per cent WWR is there in ECBC and a good architect and energy consultant will keep it low so as to maximize the building performance. Our argument is that if all the architects and consultants were following this principle, then there would probably be no need for the energy conservation code. ECBC is been made mandatory to push everyone to do what is considered energy efficient, but giving leeway to go up to 60 per cent goes against the basic logic. There are ample studies which establish that anything above 40 per cent WWR will increase the energy consumption, irrespective of the SHGC one invests in.

    3) Yes, code doesn't mention double or triple glaze units by the name. But if you go through the standard SHGC values and Visual Lighting Transmittance (VLT) mandated by the code, you will notice that these can only be met these high end glass varieties.

    4) I donÔÇÖt really understand this point. Are you referring to the payback period for these energy efficient technologies? If yes, we agree with you that money needs to be invested in cleaner technologies to reduce energy wastage. But this logic would stand no merit if applied to artificially created situations. When buildings can have inherently lower operational energy footprint by having lesser glass in our climate, it is not justified to claim green credentials by showing it could have been worse. Moreover, embodied energy and life-cycle impact of these greener technologies need to be checked. Our buildings are not only consuming increasingly more energy in operation but also in construction, something which needs to be addressed.

    Basically, the real role of regulations is to bring ÔÇÿbadÔÇÖ designs fall in line with at least the minimum benchmarks. We assume that good architects would anyways build sensible buildings with or without the regulations. Further, they would continue to raise the bar for the others. Further, the regulations also need stringent reviews. They need to be vetted and analyzed with a fine comb to ensure that they do not make architects/ customers captive users of particular products, thus pushing for their markets in India.

    Over all we have faith in our architects and energy consultants, and we acknowledge good work being done by some of them. In fact in our on-going classroom series we are captured work of some good practices around India, but sad part is we have found very few. And we believe ECBC has potential to push for more such work, but in the current state it looks like an opportunity wasted.


    Posted by: Avikal Somvanshi | 3 years ago | Reply
  • Dear Sriraj, We agree that

    Dear Sriraj,

    We agree that ÔÇ£effect of glass on heat transmission and energy consumption cannot be seen in isolationÔÇØ and that there are other factors at play too. But we beg to differ on the argument referring to ÔÇ£Factor of heat gain and over all cooling load on the system because of ÔÇ£glassÔÇØ in these buildings is nearly 2-4% at the maximumÔÇØ. There is a plethora of scientific studies which establish that area of fenestration has direct relation with the cooling load on the buildings. In fact even in cold countries like UK, questions are being raised about excessive heating of buildings due to increased glass in the building envelop during summers.

    But, several ÔÇÿexpertsÔÇÖ are recommending triple glaze units to cut down on solar heat ingress. Even our National Building Code says glass in building envelop is one of the major source of heat ingress in the building. Yes it is not the only factor but it is the most significant factor.

    Day lighting as pointed out in the article is not actually achieved by higher WWR. In fact light we receive is more of a glare which is not desirable. This is even reflected in the ECBC which asks for lower Visual Lighting Transmittance (VLT) for higher WWR configurations. Further it is a myth that higher WWR reduces artificial lighting load of the building. It is a known fact that light doesn't travel beyond 5 meter from the periphery or building envelope therefore buildings having large floor plates (which are there in most commercial buildings). As a result increasing dependence on artificial lighting even when the sun is blazing in the sky outside.

    We also like to highlight the overwhelming importance of shading buildings in our climate. The article emphasizes this; it states ÔÇ£Go back to the old fashioned methods of providing shades on windowsÔÇØ. Glass has a function in the building but like the old adage goes ÔÇ£excess of anything is badÔÇØ and that is what we are saying.

    Sensible architects and consultants are showing the way forward, and all of them agree we need to stick to 40 per cent or less of WWR, as you rightly pointed out. If this is such a well understood fact then why energy code is not acknowledging this and agreeing to an upper limit of 60 per cent?

    We have been documenting good practice for past six months now in our on-going classroom series which have steered clear of using excessive glass in their design, do check them out,.

    Thank you.


    Posted by: Avikal Somvanshi | 3 years ago | Reply
  • Dear Dr Mishra, Thank you for

    Dear Dr Mishra,

    Thank you for your encouraging words.


    Posted by: Avikal Somvanshi | 3 years ago | Reply
  • Dear Prof.

    Dear Prof. Bhattacharjee,

    Very Interesting point raised by you, it would be of great if you can share your findings with us.

    Thank you.


    Posted by: Avikal Somvanshi | 3 years ago | Reply
  • Dear Mr Bhardwaj, Very

    Dear Mr Bhardwaj,

    Very relevant issues are raised by you. Today, India is staring at a future where majority of the building stock yet to be built. This presents a unique opportunity to grow different from countries like Japan, which are efficient and profane at same time.

    Energy efficiency is important but it is the optimization of resources which is needed for a better future. We can develop our buildings differently to be less energy dependent than just merely energy efficient. This is the point we are contesting. ECBC being a national code soon to be made mandatory has the chance to propel the Indian building industry in the lesser energy dependent direction but sadly it adopted an approach which is short-sighted. And this article just points out one of the errors in its approach.

    Yes, we agree that ÔÇ£Better we collect data, analyze, compare, and benchmark and then decide what is greener? Yes, there can be greener but not green!!!!ÔÇØ. There needs to be quantification and bench-marking. Strangely the mammoth prescriptions given by ECBC have no well defined energy consumption benchmark or provision of quantification that raises suspicions about the actual intent of the code. Is it just a ÔÇ£Green FarceÔÇØ (borrowing your term)?

    Government and regulators are pushing for green without carefully doing the things you have mentioned. We share this concern. Therefore course correction is urgently required for a future which is green in the real sense.

    Thank you.


    Posted by: Avikal Somvanshi | 3 years ago | Reply
  • Dear Shankar, Thank you for

    Dear Shankar,

    Thank you for bringing in the urban heat island effect into the debate. Something which everyone in green building industry is turning a blind eye to.

    We totally agree to your observation that "this whole lobbying has now shifted from offshore to an onshore one". This is alarming and now with this lobby finding heavy representation in the committees framing and reviewing our excellent documents like the National Building Code, situation is all set to get worse.

    Nice to hear from people like you, who are not afraid to call bull a bull.


    Posted by: Avikal Somvanshi | 3 years ago | Reply
  • Hi Avikal, nice to see your

    Hi Avikal, nice to see your responses. I want to stress on the fact that I have been referring to buildings with considerable internal loads, the likes of IT offices and BPOs (core and shell) and not the likes of IHC, CSE or Development Alternatives (owner occupied buildings). The likes designed by so called "commercial firms" and not so "ecologically conscious" ones.

    To get to the points raised by you, in such buildings the factor of heat gain by increasing the glass is not more than 2-4% in general. It may raise to around 7 to 8% in badly designed buildings. When you consider internal heat gains because of people and office equipment like computers, heat gains because of ventilation (fresh air requirement) the heat gain through fabric is very less. Again only a fraction of the fabric is glass. I have done many parametric simulations myself on various buildings of this type to see the effects of different WWR and various kind of glass (SHGC and U values). The findings are that WWR of course has impact on heat gains. But, then the real killer is SHGC. The U-Value is still OK. In buildings with high above 40 % WWR the clients are not ready to go for double glazing as it increases the cost many folds, but some still consider it. Double glazing or triple glazing only impacts U-Value and not SHGC. SHGC can be reduced by either selecting technically superior glass OR by simply designing adequate shading. The problem is shading is always seen as an ugly element by the architects who cannot integrate it properly with the facade. So shading dies there.

    Having said this I am not hinting that excessive use of high technical glass is harmless. I am stressing the factors which are leading to indiscriminate use of gas and address the same instead of waging good vs bad wars with the glass manufacturers.

    1. Lack of design sense and awareness

    2. Trade off between the capital cost and operating cost as perceived by the client as it differs in owner operated buildings and tenant occupied buildings (core and shell).

    As you said, "There is a plethora of scientific studies which establish that area of fenestration has direct relation with the cooling load on the buildings", but then each building is different and please share some studies if possible.
    It is good if triple glazing units are used, but not after designing excessive glass and all the harm is done. But considering its cost factor there are very few takers to it.

    Yes, increasing WWR has no positive impact on daylight 'beyond a point'. However overall facade with sensible use and positioning of glass impacts facade design a lot. And for your information daylight if properly designed for can easily penetrate deep into floor place upto 8-9 meters or more. This does not merely imply excessive use of glass, but by carefully designing the facade, windows, lightshelves and shading. There is both mathematical and empirical evidence to it. You may visit RMX JOSS garment factor in Noida to have a look at it first hand.

    I agree shading is very important as I have mentioned above. But we cannot just go back to the same old methods of shading as we are not "working in the same of methods in the same old buildings". Functionally, yes, shading has a purpose to serve and it does not change with time. The major issue is lack of understanding of its importance and moreover the bigger issues of " design and aesthetics" among the architectural fraternity who most often fail to integrate it properly.

    One can wear a nice khaki kurta and pyjama and be pretty much comfortable in the month of August in Delhi, then why is one required to wear a "business suit" and then require to sit in air conditioned environments. I am not recommending one or the other, I am just giving a very rough comparison.
    "If this is such a well understood fact then why energy code is not acknowledging this and agreeing to an upper limit of 60 per cent?". The purpose of any code is to give a right direction at the same time not limiting the creative freedom of architects in using the available materials. It is possible to design a 60% WWR building facade more efficiently than doing a bad 40% WWR facade design. Giving an upper limit does not necessarily mean that it should be used indiscriminately. It is a freedom given that should be used in right spirit only in necessary conditions.

    I would very much like to see your documentation. Could you please provide me more links to it.
    Thanks and best regards,

    Posted by: Anonymous | 6 years ago | Reply
  • Dear Sriraj, We have been

    Dear Sriraj,

    We have been elaborating on different issues related to building in our on-going classroom series. Kindly explore our documentation of good architectural practice and building issues on our "DTE Good Living" page. http://www.downtoearth.org.in/content/green-buildings

    We hope most of your doubts will be answered in the articles featured there.

    Thank you.


    Posted by: Avikal Somvanshi | 3 years ago | Reply
  • Dear Mr Somvanshi, This paper

    Dear Mr Somvanshi,

    This paper had been published in the seminar proceedings by The Institution of Engineers (India), Pune Local Centre, and I would be glad to email a copy to you for your perusal. Please let me know the email address to which I should mail it.

    Others who may be interested in this subject and would like to see this paper can request me for the same at 'arorakl2k@gmail.com'

    Posted by: Anonymous | 6 years ago | Reply
  • Hi, I'm a journalism student

    I'm a journalism student and at present I'm doing an Investigative Project about Green buildings and the rating systems in India. I'm studying in Chennai which has 42 'green' certified buildings. Among the certified buildings is the massive, five-star hotel, the ITC Grand Chola, Asia's largest mall; Express Avenue and Ascendas IT park to name a few.

    All of them are massive glass structures which absurdly enough have received LEED ratings of 'gold', 'silver' and the likes.

    I spoke to a few green consultants and professors or architecture here in Chennai and they told me some interesting things.

    The first is that LEED has been adopted from the American version and is therefore unsuitable for Indian conditions. LEED is the most sought after rating system because of its aggressive marketing and reach. A green consultant who has worked for the IGBC went on to say that the checks are very lenient and in case of LEED pre-certifications are awarded based on SIMULATIONS, in effect, based on PROJECTED savings.
    He also said that there are several possibilities of violating the provisions once the certification has been awarded.
    In India, just as in the US, the IGBC and LEED is supported by the Confederation of Indian Industries. This is absurd. This is the case in the US as well.
    An American researcher, Henry Gifford has been able to completely disprove the claims made by the US Green Building Council. Additionally, LEED has been heavily criticized in the US by the media and academicians.

    It is a pity this is not happening in India. An architect I spoke to refused to say more about the rating systems saying that was what 'filled his pockets.'

    Maybe we need concrete data that disproves the claims made by LEED.

    I would like to thank Ms Narain for bringing out this article on Green Buildings. I have been digging for opposing views on LEED in India but there has been none. It was a delight to see the media criticizing these ratings for a change.

    Posted by: Anonymous | 6 years ago | Reply
  • The greenest building in the

    The greenest building in the modern city/suburb is one that was never built. Still, if you can plan a building that can function completely without fossil fuels (and all their derivatives); then, I'd be glad to certify it rich, deep Green. Everything else fits varying categories of greenwash and is not beneficial to the nation or our generation.

    Posted by: Anonymous | 6 years ago | Reply
  • Hmmmmm.... After such a


    After such a intense discussion , i would like to intervene with a subtle sarcasm and humble tone ( if allowed ),

    1) I dont know if glass is green , red , blue, or yellow.... I have seen it transparent. its a tool just like many others , how to use it is more important to understand .

    2) I dont support glass facade-- "I believe in language of space" earlier those buildings were giving me shade and now they throwing back some heat.

    3) Building - i believe its a 'verb' ( it is suffixed with -ing) a living organism like many . Earlier my building used to breath , but today it is on ' mechanical ventilation' ( is it dying ??? )

    4) Earlier those buildings were having 'soul' they used to talk to its occupants . Today Architecture is prostitution , buildings standing with a mascara(facade) and Architects are Pimps.. ( selling it off at higher cost) .. (ooopsss!!! i am sorry if i was harsh :) )

    5) Codes - codes are not the starting point to design a building, it is the worst case scenario which is allowed.

    6) Certification - certification is nothing but a tool used by those idiots who cant do anything but want to do something.. Trust me without that certification they would have done even worse. ( one must be happy ) The students running behind degree and marks are today's professional running behind certification.

    Dear all, today in India construction industry is going to dogs. Architects have succumbed themselves to builders, vendors and market. Architecture was considered to be a problem solving profession but in today's context role of an architect is just limited to Aesthetic appraisal. We can see impact of construction industry on an individual , it could be in terms of rising temperature, depleting ground water , contamination of potable water , increase in landfills, destruction of farmlands , and i am sure that one can relate increase in prices of Onion to construction industry. And trust me architects have major role to play in that, bottom line is that we take legal responsibility of the building we design.

    As i said architects have succumbed themselves to need of the market. The builder wants more money and he wants to build more. But as an architect are we ready to convince our clients and ask them to build less or build responsibly. And are we competent enough that we make builder earn equivalent amount of money by building less.???
    Or we all can take the easy way out, say yes to what market asks and keep up the prostitution.

    My architect friends must understand - That every line we draw has a value to it , economic , social and environmental value. So we must draw that line responsibly. Go on a site and try to build a wall, you will understand how much energy ( human energy ) it takes to raise a wall from 10 ft to 12 ft. Whats the harm in becoming responsible citizen and a responsible architect. Chose a facade responsibly and logically. And that's the simplest thing that can be done . Mies Van de Rohe said "Less is More" , try to have humble approach towards the building you create.

    Architecture in India was always labour intensive. It was always a socially responsible architecture, why are denying it in our current practices?

    We can always play the blame game that it was consultants , architects , clients or by-laws fault. But are we ready to sacrifice our ego - ( individual, communal , institutional ), understand our mistakes and make an approach to rectify them. ( i am architect thats why this post revolved around role of an architect, i know my mistake and no harm in accepting that)

    One of my friend asked me and i wish to ask you people a question " Are we ready to sacrifice our identity and come together anonymously , look for strength in everyone , have a common intent and bring positive energy and moral responsibility in path of development ?"

    Be responsible!!! Cheers

    Posted by: Anonymous | 6 years ago | Reply
  • Dear Shankarji, Thanks for

    Dear Shankarji,

    Thanks for the appreciation & kind words.

    Yes, during ancient times with design of chajjas,jaalis, better insulation,buffer spaces & other shading technology with optimum window glass size resulted into better visual & thermal comfort. But, nowadays these old sustainable practices are somehow missing by involving analysis work through shortcuts by adding glass blindly in the buildings.

    About the usage of energy efficient technology we can somewhat agree that there is lot to do further with more inclusive participation from architects, consultants & vendors. But there are many good professionals practicing nowadays who are working on awareness among building community to raise our level to design solar passive design architecture.

    Yes, taking your words in the right spirit, I am already practicing this real sustainability from quite years back. But real test & opportunity is here, where we can share our good works & methodology for the whole building community so that green building needs welcome from all section of the society without any self-interest & helps to create a better living planet.

    Posted by: Anonymous | 6 years ago | Reply
  • Dear Avikalji, Reviewing our

    Dear Avikalji,
    Reviewing our documents like NBC is not a concern because it helps us to update and practice sustainability with better approach. Because every old system & technology needs revision as per the future demands, keeping in minds all financial & technical optimization.
    These are the answered points from my end:-
    1) Allowed WWR varies from (0.1-40) %, which means in Bengaluru they have relaxed the SHGC factor with 0.4 compared with Gurgaon climate of .25.Overall, during daylight analysis we have lot of variation for selecting WWR as per the change in climatic zone. So, in end during analysis we came to have different WWR with different glass specifications for different climatic zone.
    2) Yes, I agree that all architects & consultant are not following this principle. ThatÔÇÖs where we need to make ECBC more stringent. And, if we came to conclude that we didnÔÇÖt require code & regulations then this way our way of living become more uncertain and dangerous .As, practicing ECBC is the first step towards promoting energy efficiency in the building sector.
    3) That is altogether very inappropriate to say that standard SHGC values and Visual Lighting Transmittance (VLT) mandated by the code can be met through only double or triple glaze. Many of the work where I have involved, I met all requirements of ECBC with only single glazed unit only. ThatÔÇÖs where we have to understand the role of daylight factor, shading technology like chajjas, jaali etc. which can help us in achieving sustainability, as we want to practice everywhere.
    4) That is really very understandable about high embodied energy of low e-glass which also play significant role in consuming more energy. Again, I am not in the favour of pitching glass blindly. We need to understand Glass: Myths & facts and proper analysis before coming to any conclusion. Here, I am came across with one good article about glass facades which is really very informative. Please go through this link:
    Finally, it is an important point rose from you that we need all products & technology to be vetted and analysed with all depth analysis & all around discussions. Overall, need of proper analysis and methodology based on latitude, longitude, date & time is needed with understanding of all solar passive architecture methodology. We canÔÇÖt generalize and admit that all codes & people are incorrect. There is still much good work which still motivates us to do better. As. plenty of people in society can do good work for a spurt and with immediate promotion in mind, but for promotion you want a man in whom good work has become a habit.


    Posted by: Anonymous | 6 years ago | Reply
  • Good article but the author

    Good article but the author seems to have one fact wrong

    "ECBC...goes on to set a wallwindow ratio and fixes the area of the building envelope that can be covered with glass at 60 per cent."

    ECBC limits the WWR to less than 60% and not 'fix' it at 60%-- big difference! The idea is to limit the damage of a 100% glazed facades.

    ECBC is a decent piece of work which needs to be promoted rather than loose rating systems such as LEED or GRIHA

    Posted by: Anonymous | 6 years ago | Reply
  • Agree 100% with you madam.

    Agree 100% with you madam. Either the Govt or the industry itself should set up a mechanism to measure the energy used/ saved. Without metrics it is all hogwash. For if glass exteriors are not suitable in our climate, then one should go in for an alternative design.

    Posted by: Anonymous | 6 years ago | Reply
  • Dear anonymous reader, The

    Dear anonymous reader,

    The point is that WWR of 60 per cent is allowed by the code, even after there is overwhelming agreement in the community that in hot climates 40 per cent WWR should be the limit. Contesting the phasing of the fact shouldn't be a bigger issue.

    Furthermore, ECBC is a code which fixes bare minimum efficiency standards and it should not be confused with rating programmes like LEED or GRIHA, which vouch for best practice. No doubt these ratings have grey areas which we have earlier pointed out in our publication but they have a different role to play than ECBC.

    Thank you.


    Posted by: Avikal Somvanshi | 3 years ago | Reply
  • On Saint Gobain being on the

    On Saint Gobain being on the green energy council and the subsequent raise in their sales has to be investigated. Something does not sound right, because, before the council was formed in 2001, the IT sector buildings in hyderabad area were only 20% glass like the infosys and wipro campus. Post 2004, all new buildings like the one in which microsoft is housed, the Q-city building or the new ugly ICICI buildings are 90% glass. Architects like Satish Gujral, who designed the CMC office (now TCS) used local material and designed it for local weather conditions. TCS which took over has built ugly glass buildings in this space completely over overshadowing the old structures.
    Second, the cost of building a 12 ft by 12 ft wall with bricks is more than using glass, and hence builders or developers are using glass with no regard for power consumption. The employees feel tired and suffocated in this glass cage and open the glass windows increasing the power consumption from ACs. The IT sector enjoys 100% power supply in Hyderabad while rest of the city gets at least 3-5 hours of power cut.

    Posted by: Anonymous | 6 years ago | Reply
  • Have gone through various

    Have gone through various posts and would like to bring some of the points which need to be aggressively considered.

    ECBC itself copied from mostly USA and all are relevant to them as they have complete data on weather zones clearly vetted and adopted.
    ECBC is a guideline and needs update as and when we get feedback from users which is not happening.
    ECBC does not cover social engineering, as many states give free power to agriculture i.e Farmers which was justifiable when the country had large marginal farmers who were contributing to GDP of the country.
    Now there is no small holding farmer even if they exist they are few and does not get the benefits.
    Simple when government gives free power they should supply energy efficint pumps and put a limit.
    ECBC should have been mandatory then lot of reforms improvements to the ECBC would have reformed to suit our country.
    Green building /LEED are industry supported body and any one who can pay fixed amount becomes founding member or life memeber.
    Government if they wanted to improve they should have brought ECBC as mandatory with a provision for each state to improvise the existing energy conservation intiatives and water conservation being followed,incorporated like what is being done in USA.
    Most important the water sources should be nationalized with strict guidelines, It is unfortunate we have national grid for power, Petroleum products, Milk but not for water.Excess rain gets drained into sea in almost all coastal areas.
    The national water grid should be an independant body with strict mandate to conserve water.
    Any green certified building is not even operated as per the scheme in order to save power leave alone other aspects, In most of the buildings which are green and those sitting closer to Glass for natural view are roasted especially during the summer and power outage times.

    Posted by: Anonymous | 6 years ago | Reply
  • Dear All Further anomalies by

    Dear All

    Further anomalies by simply following the USA or western technology is the ratings. Most of the equipment is rated based on the quality of water available and the HVAC equipments used are all rated for water temperature available at 29.4 degree C used for cooling the condenser i.e heat rejection.And the equipments are rated for ambient of 35 degree C ambient air.

    The water quality available are not standard it varies from different cities and quality there is no assurance especially ground water or purchased water.Normally water quality for clean water less than 150 ppm total hardness fouling is taken as 0.0005 fps units and the ratings are based on the above parameters.

    Most of the water based equipments uses water purchased by tankers either from corporation /muncipalities or purchased from private water suppliers which varies from where they are sourcing and water bleed off is not done stating it is wastage.Due to the above the water quality becomes more hard as the dust from air gets into the water used in cooling tower and condenser.

    Due to the above phenomenon the water cooled Chilling plant condenser gets scaled and operates consuming more energy or gets derated to that extent. Scaling in the condenser is removed periodically by descaling using chemicals but the piping and cooling towers especially modern imported towers gets damaged due to scaling deposits on the cooling tower fills and there virtually no after sales service.

    Many time clients have relaised the above and goes for air cooled system but do not provide adequate spaces around the air cooled condenser or cooling tower in case of water cooled units further agravating the heat rejection.

    As green building concept they have started reccommending water treatment plants or using grey water for the cooling tower make up and flushing.In most of the cases it does not happen as the quality of treated water is not as per required quality and is neither used for flushing stating the closets get colured /faded due to high iron content or the fittings get corroded due to high chloride content.

    Many buildings built as core and shell with glass facde is certified as Green with different grade, but end users are different and major design changes are made therby either the provided AC equipment is inadequate for the purpose clients takes on lease /rental.If it is oversized the inside gets high humidity and if it is not adequate then the temperature and air quantity are not maintained.

    Further complication arises as the building is taken by facility management company who are not equipped to carry out maintenance and inorder to save cost they sub contract the maintenance of plants and other utilities to any vendor who fits the bill expected by facility manager. the problem starts after few years of operation and especially during heavy rains the buildings have basements gets flooded and all the water are pumped out thereby nearby public areas like stations rods get inundated and create problems.

    Most of the buildings are constructed with limited height to get more rental space and it becomes issue when interiors are done by respective user /client and with cap you cannot have any exposed equipments and any additional space required. Dining areas are within enclosed space thereby food smell getting across all the areas. Another snacks are allowed to be taken in the seat and half eaten are thrown into dust bins inviting rodents for creating havoc.

    Most of the buildings earlier were carpeted which used to stink and now they use vitified tiles which you cannot even find water and quite a lot of accidents have happened even in established BPO's.

    Filters in air handling system are supposed to cleaned and thrown out once it is black with soot which does not happen as only sunday it can be cleaned.Facility managers maintain the documenttation clearly to collect rentals on behalf of client and pass on the burden to clients or users.

    lot of building designed for software where normally internal load is high as they pack one workstation per 40 sq.feet and the air handling units are elther over designed or it becomes inefficient after few years of operation due to faulty maintenance. Then they call the original equipment manufacturer to repair and he gives estimate for spares which will not be available locally and client wants three quotations even for proprietary parts or it has to go to the board or MD for snaction.

    Thus only single digit number of buildings are really operating closer to the green certified and many of them are not saving power nor water and only adding heat to generate more green house gases.

    None of the buildings have adequate toilets for men and women and most of the toilets are opposite to each other or inbetween AHU room which is supposed to be part of the conditioned space and generally it should be away from toilets as fresh air taken in Air handling unit room(AHU) will naturally suck air from toilet exhaust and further spoil the environment with smell.

    Regards Sridhar

    Posted by: Anonymous | 6 years ago | Reply
  • Dear All The green building

    Dear All

    The green building council as well as ECBC was and is being dominated by majority of architects and officials from companies who have become founding members by a fixed amount.

    Like population increase in cities , automobile population of the road also increasing beyond the capacity of city roads.probably India is one of the country where four wheeler or two wheeler is sold even without driving licence and are sold as commodity, which is cause for most of the accidents.

    Green building , LEED, Griha and ECBC is also in similar fashion pushed by vested interests of corporates and Only in India water bodies are coneverted to Industrial estates. Agricultural lands are converted to commercial or resdential plots therby reducing the agriculture which is the back bone of Indias food production.

    Corporates have become ESCO and spending again changing lights and Glasses to show energy is saved in next few years. Many of the so called green buildings and SEZ were feasible only because government were offering incentives.
    Although we produce more engineers than even any other country but they are not readily employable if there are they go out of the country to pursue their own interests.
    Buildings are built as green rated core and shell and in reality the buildings neither save energy nor water and only the Green stamp to get rental or lease amount more.


    Posted by: Anonymous | 6 years ago | Reply
  • The response can be headaches

    The response can be headaches or cold and flu like symptoms.
    Electrostatic or electronic filters need to be laundered regularly.
    Given that the average lifespan of a standard air conditioner is 10-15 years, those 8 year olds and above might not run as efficiently.

    Posted by: Anonymous | 5 years ago | Reply