Urban heat island mitigation with cool roof at Garden housing society, Hyderabad 

Hyderabad, the capital of Telangana, is a metropolitan city that generates industry, business, and educational opportunities. These opportunities invite an influx of the population, and the concentration of density increases the infrastructure and transportation, resulting in the city and its suburbs recording higher temperatures than its rural outskirts. This phenomenon is known as the Urban Heat Island (UHI) effect.

Kompally is a fast-developing suburb of Hyderabad with an industrial area developing at the periphery. Summer temperatures touch 40°C. Crowded settlements with the concretization of roads and buildings result in the trapping of heat. To mitigate these instances AKAH, in collaboration with the International Institute of Information Technology- Hyderabad (IIIT-H), piloted a Cool Roof Installation in a residential locality in Kompally. 

Specific case of the intervention in a neighbourhood

Garden Housing Society is a residential complex comprising of over 15 mid-rise buildings spread over 10 acres with over 850 residents. Recognizing the typology of built structures, cool roof and China Mosaic were installed on the terraces. Cool Roof refers to the application of a reflective white paint on the terrace surface that reduces the absorption of heat and lowers the surface temperature of terrace and the indoor temperature of apartments below the terrace. China Mosaic works on a similar principle, using white chipped tiles to cover the terrace surface. To monitor the difference in temperature before and after application, temperature sensors were installed in the apartments on the topmost floor. The research study was anchored by the International Institute of Information Technology- Hyderabad (IIIT-H). 

Outcomes

After the installation, thermal comfort surveys were carried out and residents confirmed that they perceived reduction in the indoor temperatures at their homes. Peak indoor temperatures reduced up to 3-4°C as tested by IIIT-H, and this brought about a change in the usage pattern of air conditioners, coolers, and fans, potentially reducing energy demand. The surface temperature on the terrace was tested post-installation showing a reduction of 15-20°C.

Inspiration

Aligning with the state policy of Telangana on Cool Roofs, the Aga Khan Agency for Habitat India, IIIT-H and National Institute of Urban Affairs (NIUA) convened a stakeholder consultation workshop on Urban Heat Island mitigation in Hyderabad, 5 January 2023. The workshop was attended by thirty participants representing local authorities, researchers, experts, and regional organizations, and discussed priorities and challenges with respect to UHI mitigation as well as key actions to be undertaken regionally and locally to build safer cities and communities and increase resilience to the increasing heat and other climate change effects.

Way forward

AKAH is planning to work on macro-level assessments for cities like Pune, Rajkot, Nagpur and build partnerships with potential funders to support the full-scale projects from assessment to action – implementation of strategies for mitigation and adaptation to urban heat through solutions like greening, cool roof, green roof, grass pavers, as well as the creation of cooling centers for relief during heat waves.