Paper published in The Journal of The Indian Institute of Architecture June 2008
Akanksha Sharma, Abhijit Parashar, Ashutosh Pathak
Akanksha Sharma (, B.Arch (JMI University, New Delhi), working with Ar.Shiraz Kidwai, Delhi Design Company
Abhijit Parashar (, B Tech (IIT Roorkee), NSE certified derivatives and capital markets dealer, currently working at Schlumberger
Ashutosh Pathak PMP, (, M. Tech. Building Science & Construction Management (IIT Delhi), Microsoft certified Application Specialist for Office Excel® 2007, currently working as Director (works), PWD, Govt. of NCT Delhi.

Author for correspondence:
Akanksha Sharma(
A booming Indian economy and consumerism has lead to exponentially rising energy consumption in Urban Indian residential and commercial structures. The per capita energy consumption levels are now inching closer to the western levels, requiring a more focused action on energy efficiency. This paper attempts to analyze the economic viability of energy efficient buildings with a life cycle costing approach. Further, an attempt has been made to enumerate the CDM benefits which can be availed of by bundling together energy efficiency improvements. The study reveals the various energy trends of building use in India, methods of incorporating energy efficiency measures into existing buildings and their financial implications. This study is expected to be useful to the designers, project stakeholders, decision makers and the academic communities.
Key words: Energy Efficient buildings, Urban Indian buildings, CDM.

Energy efficiency is a very powerful and cost-effective parameter for achieving a sustainable future. The need for investment in energy infrastructure is greatly reduced if improvements in energy efficiency are made. Energy efficiency also helps in cutting fuel costs, increasing competitiveness and enhancing consumer welfare. A stringent path on energy efficiency also leads to environmental benefits by the reduction of greenhouse gases emissions and local air pollution. Improved energy efficiency helps in securing energy by decreasing the reliance on imported fossil fuels.
The ever rising energy prices, the growing concern about depleting natural resources and climate change, raising alarms for national energy self-sufficiency govern global opinion, though are yet to affect Indian psyche in a considerable manner. Even though constant efforts are being made for securing sufficient supplies of oil, gas, etc, at affordable prices, it must be matched with immediate demand side management. In most urban locations in India, where per capita energy consumption is inching closer to western levels; there are numerous ways of reducing energy consumption in residential and commercial buildings such as offices and hotels, at zero or relatively low costs.
The energy savings achievable in an individual household might appear to be insignificant, but an extensive view regarding the population figure is necessary to understand the actual scale of savings possible. In India, 45 percent of primary fuel use is by the domestic sector. On average 55 percent of households in India have access to electricity, but since rural India is more dependent on traditional biofuels this figure falls down to 43.5 percent for rural areas [1]. The need of the hour is to increase the occupants’/ designers’ consciousness regarding the present architectural practices and energy efficiency. All those architectural practices pertaining to the aesthetics; like large glazed facades which result in higher energy demand for cooling must be considered.

Your browser may not support display of this image. In comparison to the energy consumption in buildings in the developed countries, the Indian buildings consume more energy per ˚C especially for heating and cooling. The National Building Code of India has classified the Indian Climate into five zones: hot-dry, warm humid, composite, temperate and cold. With reference to these classifications; the total specific energy consumption for conditioned buildings may range from 280 kWh/m2 to about 500 kWh/m2 compared to less than 100 kWh/ m2 in temperate climates [2]. Significant reductions in energy use in buildings can be achieved using mature technologies for energy efficiency that already exist widely and that have been successfully implemented. A major portion of these savings can be accomplished in ways that reduce life-cycle costs, thus providing reductions in CO2 emissions that have a net benefit rather than cost. Occupant behavior, culture and consumer choice and use of technologies are the major determinants of energy use in buildings and play a fundamental role in determining CO2 emissions.
Because of booming infrastructure, construction is one of the largest energy consuming sectors in India. A much more sincere use of energy in our homes and offices with a little or no investment can result in a 10 percent reduction in energy consumption thereby making a significant impact on national energy requirements. When building a new house, office or hotel, issues relating to building design should be considered which will affect the energy consumption. India has a great potential for the use of renewable energy technologies, yet it is very important to reduce the loads in the building before considering how the energy is supplied.
It is important to consider the energy use in the present buildings because we replace old buildings with new ones only at a very slow rate.
In line with the Pareto principle, the first step in an energy efficiency approach would be to find out the places/areas/functions in the building where the energy consumption is maximum. An energy audit will help in highlighting those areas and identifying the most effective measures for cutting the energy costs. The energy audit evaluates the efficiency of all building and process systems that use energy. The process includes all the utility meters, locating all energy sources coming into a facility and then identifying energy streams for each fuel, quantifying those energy streams into discrete functions, evaluating the efficiency of each of those functions, and identifying energy and cost saving opportunities. The audit generally includes identifying all energy systems, evaluating the condition of the systems, analyzing the impact of improvements to those systems and writing up an energy audit report.
There are various contexts and measures to improve energy efficiency in existing buildings such as when adding extensions, carrying out alterations and maintenance or solely as an improvement measure. Existing buildings report for the major part of energy use in buildings for the projected future. According to various surveys, it is estimated that buildings could save 10-15 percent on their energy bills by implementing energy efficiency improvements, which not only make the environment more comfortable but can also yield long-term financial rewards [3]. The proposed solutions for saving energy may apply throughout the buildings from the roof, walls, and insulation that enclose it to the appliances and lights inside.
A number of small steps and a cautious approach may considerably help us to make our homes, offices, industries etc efficient consumers of energy thereby adding value to the energy supply and demand of the nation.
4.1. HVAC
If the air conditioning system is 10 to 20 years old, it needs to be replaced. There are significant energy savings from pulling the older air conditioning units out as they consume greater electricity. Following parameters must be kept in mind, while designing a HVAC unit:
    • An air-conditioner will work lesser and consume lesser electricity if the condenser is in a relatively cool place. Therefore, as far as possible, condenser unit should be placed in a shady location of the building. A unit working in the shade draws on as much as 10 percent less electricity than the similar one operating in the sun.
    • A room air-conditioner that is too large for the area it is supposed to cool will perform less efficiently and less effectively than a smaller, properly sized unit because room units perform better if they run for relatively long periods of time than if they are continually switching off and on. A more constant room temperature is maintained and excess humidity is removed if the air conditioners are run for longer times.
    • Moreover, the thermostat should not be set at a colder setting than normal when the air-conditioner is switched on as it will not cool the home any faster and would consume more energy by excessive cooling.
With technological advancements, an intelligent environmental room air assist system can be provided for improving air quality/conditions in a room of a building where the typical room air temperature is generally governed by a building HVAC system. The intelligent environmental air assist system of the building basically includes a multitude of sensors, where each sensor provides a sensor signal indicative of a selected air quality parameter in the designated room. Environmental air-assist components or modules are located in the designated room, where each of the environmental air-assist components is responsive to a selected command signal for affecting, at least in part, at least one of the air quality parameters. A signal processor generates air assist component command signals so as to achieve an environmental air quality in the designated room as required by its users.
Solar control and insulation film reduces solar glare, summer heat gain and winter heat loss, thus reducing energy costs all year round. Solar Control Film can reflect 83% of the sun’s glare without blocking the natural light, and reject up to 80% of solar heat gain, cutting air conditioning costs. Insulation Film combined with solar control film, retains interior heat in winter, cutting heat loss through glass by up to 30% and reducing heating bills. Studies have shown that solar control window film can pay for itself in less than 5 years in terms of the energy savings on air-conditioning costs alone.
The heating bills can also be reduced by the combination of both solar control and insulation properties in the same window film. Just as glass allows solar heat to radiate through it in summer, it also allows interior heat to escape through it in winter. However, low emissivity solar control film also provides insulation benefits, reflecting back up to 30% of the heat; which would normally be lost in winter.
This means that the addition of low emissivity solar control film to single glazed windows can retain as much heat as double glazed windows. Hence buildings fitted with these technically advanced solar insulation films benefit from dramatic savings in air conditioning energy costs in the summer and heating energy costs in the winter.
The following chart shows the lifecycle cost of AC with and without the use of solar films and insulation over a period of ten years.

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In India, 28% of the residential electricity consumption is by the lighting sector [4]. The use of inefficient lighting options despite more efficient alternatives existing is the major cause responsible for this figure. This is not only a squandering process of energy that is in short supply, but also results in the release of millions of tons of carbon dioxide, the biggest contributor to climate change. Lighting energy use can be reduced by 75 to 90% compared to conventional practice through (i) use of day lighting with occupancy and daylight sensors to dim and switch off electric lighting; (ii) use of the most efficient lighting devices available; and (iii) use of measures such as ambient/task lighting [5]. Lights that used to be put inside a building 10 years ago are 50 percent more inefficient than lights that are used today. Lighting replacement generates lesser heat thereby allowing the building to remain cool whenever necessary.
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This infra red image highlights the amount of energy wasted as
heat in an incandescent bulb (left) as compared to a CFL(right).
Replacing standard light bulbs and fixtures with compact fluorescent lamps (CFLs) and using lighting controls such as occupancy sensors, dimmers, or timers helps to reduce lighting energy use. Low energy fluorescent bulbs consume one-fifth the energy of conventional tungsten bulbs but give the same light output, and reduced CO2 emissions. Moreover, they last 9,000+ hours longer than incandescent bulbs and emit only one-fifth of the heat into the room, thereby considerably reducing cooling requirements. [6]

Cost benefit analysis of CFL v/s Compact Florescent Lamps
Comparison Incandescent Lamps Compact Florescent Lamps
Rated Watts 80 20
Lamp Life (Hours) 750 10000
Cost per kWh(residential) $ 0.08 0.08
Cost per bulb ($) 0.4 8
Total life cycle cost 69.2 24

T-12/T-8 lamps are the most common lamps used in office and residential buildings which can be replaced with T-5 lamps of 28 watt at a cost of about 20$ with retro fitting arrangement. This whole process helps a lot in saving energy as the normal life of 28 watt T-5 lamps is 15000 hours and replacement cost of tube is about 4.5$ as against the cost of .8$ for T-12/T-8 lamps whose life is about 5000 hours[7].
PIR (passive infrared) sensors can be used in buildings so that they "switch off and switch on" lights in the event when nobody is available in the specified room. These sensors work on the principle of the heat of the individuals and accordingly a have reasonably good performance with a life expectancy of around 10 years. The cost of such sensors is 150$ each. The use of sensors is expected to produce energy saving of about 15-20% [8]. Adoption of these methods both in the existing as well as in the new buildings without much increase in the cost of lighting per brings energy consumption due to lighting to around 60 %.
Greenpeace has called for an immediate move towards a progressive legislation to phase out inefficient lighting as an immediate step to increase energy efficiency in the country. It says that all lighting products that have an efficacy of less than 25 lumen/watt (minimum efficiency threshold) should be banned from 1. 1. 2010. By1. 1. 2012, the minimum efficiency threshold should be increased to 35 lumen/watt and by the 1. 1. 2015 the marketing of all products below the efficiency threshold of 55 lumen/watt should be banned from the market [9].
Solar radiation is abundant in India and should be utilized wherever possible for water heating. The technology is well established and it can easily be fitted to existing and new buildings. Adding a solar collector and a large storage tank (for cloudy days) can reduce electricity consumption for water heating (by 40 to 90%) thereby making great economic sense. The basic requirement is shadow free space facing south @110 Sqft per KW. One KW system produces 4 to 6 units of electricity per day depending on sunshine and costs around 6500$ depending upon system configuration [10]. The cost of installing a 100 liter warming capacity solar panel is 375$- 500$.
4.4. GLASS
A building needs energy primarily for three functions: heating, cooling, and lighting. Glass can tremendously affect the efficiency with which these functions are carried out. New products like body-tinted glass or glass with solar control coatings can control the percentage of light, solar radiation, and heat that is transmitted into a building.
The thermal performance of windows can be improved greatly through the use of multiple glazing layers, low-conductivity gases (argon in particular) between glazing layers, low emissivity coatings on one or more glazing surfaces and use of framing materials (such as extruded fiberglass) with very low conductivity. Glazing that reflects or absorbs a large fraction of the incident solar radiation reduces solar heat gain by up to 75%, thus reducing cooling loads.
Depending upon the requirements glass usually costs anywhere between .625-250$ per sq feet, treated glass costs 60 per cent more than normal glass. But the initial investment has a payback period of less than five years — in the form of reduced electricity bills. It is estimated that with the decrease in unwanted heat gains and reduced air conditioning loads, one square meter of EEG- energy efficient glazing can save up to 70 units (kWh) of electricity per year [11].
Common energy saving methods includes double glazing, loft insulation, draught proofing and cavity wall insulation. Broken china mosaic can be used over the roof tops for providing heat reflective surface. In a composite type of climate it can result in a heating/cooling load reduction of about 40%. Nowadays energy-saving wall coats are being designed to insulate and waterproof exterior walls. These coatings have a very low conductance; it is the combination of their high reflectance, high emittance and endothermic effect what makes them a very good choice for protecting the exterior walls from heat buildup. Insulating the walls and ceilings can save 20 to 30 percent of home heating/cooling bills and reduces CO2 emissions. Planting shade trees and painting the house a light color if in a warm climate or a dark color if in a cold climate can save a lot of energy in the form of decreased cooling loads. Reductions in energy use resulting from shade trees and appropriate painting can save up to 2.4 tons of CO2 emissions per year [12].
Sustainable and energy efficient buildings generally incur a "green premium" above the costs of standard construction. They also provide an array of financial and environmental benefits that conventional buildings do not. These benefits, such as energy savings, should be looked at through a life cycle cost methodology, not just evaluated in terms of upfront costs. From a life cycle savings standpoint, savings resulting from investment in sustainable design and construction dramatically exceed any additional upfront costs. The costs and savings involved can be classified as:
First Costs/Savings are the costs and savings from incorporating green features into a building. They will vary significantly depending on the specific project goals. While there are many significant benefits that shall involve no additional cost to be implemented (e.g., South facing windows), some features will cost more in both design and materials costs. Estimates for additional first cost are as low as 0-3%, for LEED Certified, to 10% or more for higher LEED ratings. However, this does not include the tax benefits and interest rate deduction offered, and thus would be actually lower then the above value. [13]
Life-Cycle Costs/Savings are the costs/savings over a building's or feature's useful life .The energy savings from a life cycle costing approach can be up to 80% of the total energy costs.
A minimal increase in upfront costs of about 2% to support energy efficient design would, on average, result in life cycle savings of 20% of total construction costs -- more than ten times the initial investment. This implies that the ROI on energy efficient buildings can be around 20-40%, plus an additional higher asset value for the building. Also, the ROI from energy efficient lighting is somewhere between 50-80% which implies a payback period of less than 2 years, making a very strong case [14].
A detailed review of 60 LEED rated buildings clearly demonstrates that energy efficient buildings, when compared to conventional buildings, are:
    • On average 25-30% more energy efficient;
    • Characterized by even lower electricity peak consumption;
    • More likely to generate renewable energy on-site; and
    • Very likely to provide an opportunity to encash upon CDM benefits in the near future. [15]

Reduced energy used in Energy efficient buildings


Certified Silver Gold Average
Energy Efficiency(above standard code) 18% 30% 37% 28%
On-site Renewable energy 0% 0% 4% 2%
Green Power 10% 0% 7% 6%
Total 28% 30% 48% 36%
              Source: USGBC
In Indian government buildings alone, the investment potential has been estimated at 76 million $ for energy efficiency projects (having over 500 kW connected load for individual facility) in 36 cities. Overall energy savings potential has been estimated at 760 GWh. At 15% capital recovery factor, cost for every kWh avoided works out to about $ 0.12 while unit cost of supply from new generating facility would be about $ 0.12. It has also been estimated that air conditioner facility improvement will require about 80% of the total investments whereas light will require 10% of the investments. [16]
The Clean Development Mechanism (CDM) is an arrangement under the Kyoto Protocol allowing industrialized countries with a greenhouse gas reduction commitment (called Annex 1 countries) to invest in projects that reduce emissions in developing countries as an alternative to more expensive emission reductions in their own countries. An important feature of a carbon project is that it establishes additional incentive through emission reductions credits.
Building sector energy efficiency projects can qualify as CDM provided that they achieve real and measurable emission reductions. The Indian building sector offers a huge potential for greenhouse gas reduction, but only a small part can realistically be tapped by the CDM. This is due to the fact that transaction costs may be prohibitive for all but the biggest commercial buildings or large-scale appliance diffusion programs.
The initial focus of the CDM projects should be on service sector buildings such as hotels, headquarters of banks and large companies with high specific energy consumption and with large potential for energy savings. Also, large organizations, including the central/state governments (50 % of all buildings are being built by or for the public sector in India) can decide to bundle together their buildings to gain enough scale required for CDM benefits.
Despite the relatively favorable general policy framework to support energy efficiency, there are several barriers to the actual implementation of these measures. The identified barriers range from the still inadequate legal and regulatory framework that limits the role of Energy Service Companies (ESCOs) and the lack of a coherent system of energy planning to different information, "capacity" and financial barriers.
On the basis on the study undertaken following general conclusions may be drawn:
  • India's energy intensive infrastructure growth coincides with an era of ever increasing energy prices, and our energy security policies need to include implementing energy efficiency techniques in a big way. Some of the key barriers to the implementation of economically feasible energy efficiency measures in buildings are related to the costs and the associated risks of the project preparation stage.
  • The Indian government is the largest consumer of electricity and since the exchequer directly pays the energy bills, efficiency has been at a very low priority. Even though Bureau of energy efficiency has come up with the Energy Conservation Building Code 2006, implementation has lagged far behind policy. In the public sector, only NCR has shown some initiative.
  • Private sector buildings are increasingly aware of the life cycle costing approach and with the recent availability of a parallel LEED-INDIA rating system for Green Buildings, a lot of action and activity can is expected. The rising energy prices shall further make lifecycle costing more relevant.
[1] ‘The importance of energy efficiency in buildings’ D.J. Harris, and R. Madomercandy, School of the Built Environment, Heriot-Watt University, EH14 4AS, Edinburgh, UK,, BEE Newsletter, Volume 6. Issue 4-6, February-June 2006
[2], [15], [17] Indian Urban Building Sector: CDM Potential through Energy Efficiency in Electricity Consumption,Authors: Inderjeet Singh, Axel Michaelowa, 2004, ISSN 1616-4814 .
[3], [6] ‘The importance of energy efficiency in buildings’ D.J. Harris, and R. Madomercandy, School of the Built Environment, Heriot-Watt University, EH14 4AS, Edinburgh, UK,, BEE Newsletter, Volume 6. Issue 4-6, February-June 2006
[4], [9 ] ‘100 Months To Prevent Climate Chaos’-phase out inefficient lighting and cut India’s Carbon emissions by 5%, Greenpeace,, November 15 2007
[5] Residential and commercial buildings: Coordinating Lead Authors- Mark Levine, Diana √úrge-Vorsatz,- fourth assessment report- Intergovernmental Panel on Climate Change (IPCC), Working Group III, Hungary, 2007,
[7], [8]. Energy Efficiency Improvement In Buildings by N. Nagarajan, Chief Engineer (Elect.),CPWD,

[10] ‘Solar Power Super Power-- Atanu Dey on India’s Development,, November 22nd, 2003

[11] ‘Say yes to energy-efficient windows’, Bibek Bandyopadhyay, Director, Solar Energy Centre, Ministry of Non-Conventional Energy Sources, Government of India, ,, BEE Newsletter, Volume 6. Issue 4-6, February-June 2006
[12] ‘Twenty Things You Can Do to Conserve Energy’ -
[13] “Greening Up Your Bottom Line”, Jan Harris and Tom Hengelsberg ,, September 25, 2007 .

[14] “Part 2: Averting Climate Catastrophe”, Green party of Canada,


Fig 1- Residential and Commercial Sector Energy Consumption

Fig 2 –Life cycle cost of AC

Fig 3 – Energy Wasted- CFL and incandescent lamp

Table 1 - Cost benefit analysis of CFL v/s Compact Florescent Lamps

Table 2 - Reduced energy used in Energy efficient buildings


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