The Indian real estate industry has projections of 230 million housing units in urban areas by 2047, accommodating 51% of India's population. With increasing aspirations of building occupants and a warmer climate, air conditioning demand will to grow 11-fold by 2037-38 compared to 2017-18.
While India's Eco-Niwas Samhita (ENS), the residential building code launched in 2018 includes a maximum Residential Envelope Transmittance Value (RETV), which calls for reducing heat transfer through the building envelope, industry practitioners are meeting this requirement by incorporating insulation into the building envelope.
This paper demonstrates that for residential buildings in cooling dominated climates that are naturally ventilated for cooling, increased insulation is counter-productive. Various building envelope assemblies and insulating values are evaluated for thermal comfort conditions in a hot and dry climate. Simulations were conducted using DesignBuilder for summer conditions. Results have also been compared with measured data.
The findings indicate that insulated walls can increase discomfort hours by 4% compared to uninsulated walls. In contrast, high thermal mass envelopes improve comfort hours by 3% and 8%, respectively, suggesting they are more effective for naturally ventilated buildings. The results highlight the need for re-evaluating the residential energy code as well as the current practices of implementing the energy code in India.
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