Thermally uncomfortable mass housing can stop India’s National Cooling Action Plan from achieving its target of reducing cooling energy need by 20-40 per cent by 2037-38

Ensuring thermal comfort in mass housing, therefore, must be a part of the post-coronavirus outbreak ‘green’ recovery strategy: CSE 

  • About 1-1.2 million new dwelling units will be built in India in the coming years – it is important to ensure that the economic shock triggered by the pandemic does not derail our efforts to improve thermal comfort in these buildings 
  • Increased focus on building affordable housing quickly is leading to the use of alternative material and technologies to save time and cost – but this is happening without a strategy to ensure thermal comfort improvement. This is worrying, when India’s residential sector is adding an estimated 178 million sq m of residential floor area every year 
  • CSE analysis shows that a combination of well-assessed material and architectural design is important to increase thermally comfortable hours in affordable housing 
  • It is necessary to link regulatory and fiscal strategies for green recovery with affordable housing and rental housing based on mandatory adoption of thermal performance criteria 

New Delhi, September 29, 2020: A new assessment by Centre for Science and Environment (CSE) bears out the dangers of ignoring the need for thermal comfort in mass housing and neglecting linking fiscal strategy to improve thermal comfort performance – something that must be a part of the new post-pandemic green recovery agenda.    

Releasing the assessment here today at a webinar and online round table meet, Anumita Roychowdhury, CSE’s executive director-research and advocacy pointed out: “According to real estate industry estimates, about 1-1.2 million dwelling units are likely to get added to the formal housing stock over the next few years. Not linking the current fiscal support strategy with mandated improvement in thermal comfort in buildings can delay thermal comfort measures and lock in enormous energy inefficiency during the operational phase of buildings.” 

Added Rajneesh Sareen, programme director, Sustainable Buildings and Habitat programme, CSE: “This can compromise India’s Cooling Action Plan target of reducing cooling demand by 25-30 per cent and cooling energy requirement by 20-40 per cent by 2037-38. According to the Bureau of Energy Efficiency, energy demand in buildings can be cut down by up to 40 per cent by designing an efficient envelope. 

The CSE assessment contends that the COVID-19 pandemic has reinforced the need to look at housing layouts, building design and choice of materials for addressing thermal comfort, improving liveability and reducing disease burden in our homes. All the verticals under the Pradhan Mantri Awas Yojana (PMAY) need to address this -- including the Affordable Rental Housing Complexes that has been added as the fifth vertical by the Union Ministry of Housing and Urban Affairs. This requires mandatory provisions of thermal performance requirements in mass housing. 

Key highlights of the assessment 

Speed of construction and influx of new walling material 

It is estimated that monolithic wall panel made of poured concrete with thickness of 100 mm wall can have thermal transmittance value that determines the heat gain in the building – at 60 per cent higher than the conventional brick wall. This demands benchmarks, toolkits and guidance along with mandate to influence walling assembly approaches, insulation layers, shading and orientation approaches.    

Says Sareen: “CSE’s assessment of the new buildings design of affordable housing in selected sites in Telangana shows that the same design when simulated with AAC block with 150-mm thickness, leads to a gain of about 150-160 thermally comfortable hours annually over the base case of wall made of concrete of 150-mm thickness. The gain in thermally comfortable period increases dramatically to 272 hours when AAC blocks of 250 mm thickness are used with proper window shading. Thus, mass housing needs a mandate and benchmark for materials and design (orientation, shading and building geometry) for thermal comfort and to reduce air conditioned hours. This requires guidance on orientation, surface exposure and shading devices.” 

Link fiscal support with thermal performance 

Extensive fiscal support is being provided under the PMAY for affordable mass housing. The government has reduced taxes, GST has been lowered from 8 per cent to 1 per cent, there is mandatory exemption from stamp duty and other levies, and extra floor area ratio and transferable development rights are granted to compensate for the lower profit margin in the sector. 

The additional costs of thermal comfort design, material and walling assembly need to be addressed. The estimates shows that the combined impact of material choices (based on these new technologies) and architectural design solutions can push up the incremental cost by about  20-35 per cent compared to conventional construction considering the current construction costs and material penetration in states. The current fiscal strategy will have to address this. 

If not addressed, the burden of the extra cost of meeting thermal comfort requirement will fall on the beneficiaries. Any stimulus for the sector should be performance-based. This will also require better assessment of affordability in different markets based on better profiling of income to housing prices, price to income ratio etc.    

Fiscal support to new materials needs to be linked with mandatory thermal comfort attributes: The Ministry of Housing and Urban Affairs has taken an important step forward to support and fast track rental housing in response to the migrant crisis during the pandemic. The new vertical - Affordable Rental Housing Complexes (ARHC), for ease of living for urban migrants and the poor acknowledges COVID19 and reverse migration of workers, the compromised living conditions in slums and the need for ‘dignified living’. This has linked Technology Innovation Fund with the new generation materials and BMPTC is responsible for creating the compendium of materials with their attributes including thermal performance, as well as assess their adoption in housing under PMAY and rental vertical. 

The additional Technology Innovation Grant for the projects using innovative and alternate technology is linked with speed of construction, sustainable resource efficient and disaster resilient construction. But the sustainable resource efficiency need to be defined to include mandatory thermal comfort within its scope to include requirements of ECBC-R for better adoption of design and orientation approaches for improved thermal comfort. Material choices need to be informed with specific indicators on orientation correction, natural ventilation, improved shading, enhanced thermal resistance, and reduced surface exposure to reduce the heat load on the structures. Performance criteria will improve operational efficiency and increase thermally comfortable hours in a year helping to reduce the need for air conditioning that has huge energy penalty. 

The way ahead

Speaking at the webinar, CSE director general Sunita Narain said: “Moving towards a ‘thermal comfort for all’ approach and making a thermal comfort standard as the central focus of building regulations and practice -- as the India Cooling Action Plan has asked for -- will require a diverse and broad-based approach. While taking steps to frame and operationalise thermal comfort standards for buildings, we must combine design and technology to reduce the thermal load on buildings and operational hours of active cooling.” 

What the CSE assessment recommends:

  • Guide the housing sector on alternative material and construction technologies
  • Promote adaptive thermal comfort standards
  • Need fiscal strategies to minimize cost of improving thermal comfort and new construction technologies. Otherwise beneficiary will end up paying the operational cost.
  • Developing thermal performance criteria for funding and link subsidies and incentives with performance of the housing stock
  • integrate regulatory instruments like EIA, building byelaws, etc. with thermal performance criteria. Disclosure systems will be a must.
  • Shift policy focus from only constructing the housing stock to green performance and lowering of operational cost burden for beneficiaries. Expensive new walling technologies bear a high risk of increasing beneficiary’s household energy expenditure
  • Need improved criteria for assessing affordability establishing affordable housing price-to-income ratios in cities in the post COVID-19 scenario
  • Need instruments of accountability and a disclosure system for availing incentives 

For more on this or for interviews etc, please contact Sukanya Nair of The CSE Media Resource Centre at, 8816818864.


To access the webinar proceedings and the CSE assessment, please cick here




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