Thermal Comfort and Integrated Daylight

With increasing population, rising temperatures and frequently occurring heat waves, thermal comfort in the built environment is bound to drive the health and wellbeing of India. ‘Thermal Comfort for All’ in an energy efficient and climate friendly manner is vital. Designing energy efficient buildings for reduced heat load, mainstreaming adaptive comfort approach, maximizing daylight illuminations and cutting down the over-dependence on refrigerant based air conditioning are central to India’s energy security and climate change mitigation efforts.

In this context MT CoE’s work on thermal comfort and integrated daylight systems is devoted to create the knowledge base, research and guidelines, policy frameworks, and user-friendly toolkits that promote sustainability in the building sector. The Centre is developing design guidelines, prescription guidebooks, a design-based tool; Eco-Niwas Samhita design aider and flyers for achieving better thermal comfort and daylight at low cost in cooling dominated Indian residential buildings.

The adoption of prescription guidelines and ENS design aider tool will support the government initiatives to ensure ‘Thermal Comfort for All’ especially in the affordable housing sector, cutting down the over-dependence on refrigerant based air conditioning systems and consequently contributing towards the India’s energy security and climate change mitigation efforts. The availability of research outputs in the public domain is intended to raise awareness among relevant stakeholders on various aspects of thermal comfort, daylight systems, energy efficient design strategies, codes and standards.


In light of the government’s commitment to construct 20 million affordable houses under Pradhan Mantri Awas Yojana by year 2022, pledging ‘Thermal Comfort for All’ in an energy efficient and climate friendly manner is crucial. In comparison to thermal comfort, daylighting aspect is often neglected during the building envelope design, whereas daylighting can contribute to significant reduction of lighting energy loads. India needs to develop energy-efficient strategies focused on the residential sector to limit the current trend of unsustainable escalating energy demand. Thus, to reduce energy loads and improve occupant comfort ‘energy-efficient affordable housing’ has been a key to facilitate the process of urbanization. The current trends of residential envelope design and construction practices show an immense variation in heat gains and hence in sensible cooling demand. Therefore, ‘Integrated daylight systems for affordable housing in India’ and ‘Thermal Comfort prescription for cooling dominated Indian Residential buildings’ guidebooks have been developed to understand the process of building design of a residential building located in cooling dominated regions following the prominent standards, policies and available guidelines for minimizing the cooling load, energy costs, and maximize thermal comfort and illumination. These guidebooks act as another step forward in providing relevant information to designers and practitioners to build thermally comfortable, day-lit, energy-efficient built environment.

Eco-Niwas Samhita Design Aider Tool

Eco-Niwas Samhita Design Aider is a unique, user-friendly, design-Based tool developed under the scope of the activity of thermal comfort and integrated daylight systems. When designing for an energy-efficient residential building, one of the crucial elements to keep in mind is the amount of thermal comfort and daylight we can achieve by incorporating effective walling, glazing, shading, and roofing assemblies. This tool has the potential to help the user to devise the different combinations of these assemblies and select the optimized sustainable solutions to meet the compliance for Visual light transmittance (VLT), Openable window to floor area ratio (WFRop), Thermal transmittance of roof (Uroof) and Residential envelope transmittance value (RETV) for affordable housing at preliminary/pre-construction design phase. The tool has been pilot tested and validated for various real-time projects in-line with the Eco-Niwas Samhita 2018 benchmarks. The tool puts to use the database of materials tested at CoE for its thermal properties and enables the appropriate selection of building materials to the designer. Thus, the user will be able to select different materials from a robust in-built building material database for comparing multiple projects simultaneously and visualize the contribution of each of the three calculation terms (Term-1, 2, and 3) of RETV. The interpretation of each term available on the tool will further assist the user to understand the intervention areas and further improve the design. The ENS Design Aider Tool also presents a set of recommendations for maximizing thermal comfort and daylighting in the five climatic zones.

Perception Study for Indian Residential Buildings

An online survey is being conducted pertinent to this project sub-activity focused on Integrated Daylight Systems & Thermal Comfort for Cooling dominated Indian Residential Buildings. The objective of the survey is to ascertain the approach followed by building designers & practitioners on a day-to-day basis and identify the gaps in the design of residential buildings for occupant thermal comfort and daylight. This will help in establishing the predominant design practices and considerations that significantly impact the occupant thermal comfort and energy consumption in residential buildings. The survey results will further be incorporated into the work-in progress design guidebooks and web tool as well as utilized in the outreach activities.

We invite you to provide your expert opinion using this survey link.