Million Cool Roofs Challenge

Accelerating access to affordable, sustainable cooling through rapid deployment of cool roof materials

What is the Million Cool Roofs Challenge?

The Million Cool Roofs Challenge is a global competition to rapidly scale up the deployment of highly solar-reflective “cool” roofs in developing countries suffering heat stress and lacking widespread access to cooling services. 

Run by the Kigali Cooling Efficiency Program (K-CEP) in collaboration with the Global Cool Cities Alliance, Sustainable Energy for All and Nesta Challenges, the US$2 million challenge awarded US$100,000 grants to teams to deploy solar reflective coating and/or materials in an eligible country. In 2021, US$1 million will be awarded to the team that has demonstrated the best sustainable and transferable model for rapid deployment of cool roofs and meets the judging criteria.

Why are we doing this?

Cooling is fundamental to the supply and storage of food, medicine and vaccines, and for ensuring the quality of life and productivity of citizens. Yet around the world millions of people die every year from causes related to a lack of access to cooling.

Reflective building surfaces reduce the demand for cooling energy for those that can afford it while also providing a sustainable passive cooling solution for the billions of people who do not have the economic means to access mechanical cooling options, in poor rural areas, urban slums and homeless shelters.

Reflective roof surfaces not only have an impact on individual buildings, but deploying them across a whole community can have a net effect on reducing local ambient temperatures. Further, the deployment of reflective materials creates sustainable jobs and skills opportunities for low skilled workers in both rural and urban contexts.

1.1 billion people...

face access to cooling risks across the world, including 630 million slum dwellers living in hotter-climate urban areas

Replacing a dark roof with a white roof...

can cool the top floor of the building by 2 to 3 degrees Celsius

2.3 billion people in developing countries...

are likely to only be able to buy the most inefficient and energy-intensive air conditioning models, associated with higher greenhouse gas emissions


Cool Roofs will be implemented by the South African National Energy Development Institute (SANEDI), in partnership with local municipalities. This project is aimed at scaling cool roof solutions in RDP (government subsidised) homes throughout South Africa. In each municipality selected, the team intend to deploy at least 25,000 square metres of cool roofing and spread awareness of the benefits of cool roofs among the communities. Working with a professional labour management company, SANEDI will train unemployed local residents to apply the specialised coating in their communities.

Cool Roofs Piloting Initiative in Niger (COROPIN) is an initiative of Mercy Corps. This project is designed to stimulate the private sector and create a market for cool roof solutions and products in Niger, while raising awareness and fostering demand for cool roofing solutions. The team plan to achieve this through demonstration projects targeting several levels of engagement: community, local government, national government, private sector, and the general public.

Cool Roof Transform Project Cote d’Ivoire is led by Social Tech in partnership with MonArtisan. Through this initiative, the team will mobilise schools and the surrounding communities to recycle plastic waste and sell it on to recyclers, thereby generating the funds to deploy cool roofing. They will then tap into MonArtisan’s network of painters to apply the coating. The team aim to fund the first 40,000 sqm of cool roofing as a demonstrator project, with the remaining 60% financed by the income generated from the recycling.

Cool Roofers Senegal is an initiative of Cool Roofs France in partnership with Dakar-based eco-construction company Elementerre Sarl. This project is aimed at deploying highly reflective paint to roofs in households and public buildings in low-income neighbourhoods in Dakar. The initial pilot project aimed at coating five buildings will kick off a more comprehensive strategy of technology transfer, training and support to local partners, eventually scaling to 50 buildings in the locality. Cool Roofs France later plan to scale throughout Senegal and beyond, boosting job creation and increasing affordable access to cooling throughout Africa.

Cool MEANS will be delivered by a partnership of three organisations: Arup, Echale and New Story. The team aim to deliver access to cooling in low income households in Mexico by integrating commercial paints in the standard housing designs of Echale and New Story. The project will begin with a pilot building to identify and test material supplies, prototype installation methodologies, deliver preliminary training and collect data to validate performance predicted with the simulation tools. They will then produce a toolkit to allow their solution to be scaled up incrementally to other buildings in the community.

Use of Innovative Indigenous Materials for Thermal Comfort will be implemented by BRAC University in collaboration with local government, business and academic stakeholders. The team aim to conduct a randomised controlled trial comparing three different strategies for reducing indoor temperature in low income households in Dhaka, including indigenous insulating materials such as dense coir and bamboo mats. This will use a mixed method approach, with community engagement and focus group discussions supplementing the quantitative testing.

Cooling Rwanda 2020 will be led by the Rwanda Green Building Organisation, with GreenA Consultants acting as their technical partner. This project is designed to alleviate cooling challenges in Kigali and beyond, beginning with a number of demonstrator projects and awareness campaigns in homes and a variety of government, commercial, and public buildings. The second phase of the project, from March 2020, will see the launch of training and entrepreneurship programmes and business matching platforms aimed at scaling the project’s success.

Driving Climate Action to Combat UHI with @CoolRoofs Tangerang is an initiative of Universitas Pendidikan Indonesia (UPI), in partnership with the Tangerang Municipality, University of Florida and Milenium Solutions USA. The team will run a pilot project deploying cool roof materials on six residential, community and public buildings in the Tangerang municipality of Indonesia. This benchmark project will then be replicated in other municipalities and cities within Indonesia to achieve 1 million square metre coverage. As part of their project, the team will raise public awareness of cool roofs, provide training programmes in cool roof installation, and scale up local supply chains.

Sumasalamin Sa Sun (Tagalog, meaning “Reflect the sun”) is an initiative of Cornland International and Carbonergy Business Consultancy Services. The aim of this initiative is to test a business model for providing services to paint corrugated metal roofs in the Philippines with high-quality reflective coating. As a pilot, the initiative will target approximately 100 low-income homes, working with charities, 50 homes in impoverished areas, representing a combined roof area of up to 6,000m2. The goal moving forward is to expand to commercial, industrial and municipal establishments (e.g. schools, hospitals, community buildings) and coat 1 million m2 by the end of 2020.

Topps Seal Coating to Create Reflective Roof Surfaces will be implemented by Steam Plant Ltd in partnership with Topps Products. Based in Nairobi, the Steam Plant team will work with local leaders to sensitise the target communities to the benefits of cool roofing. The project will focus on recruiting and training young people to carry out pilot cool roof projects on key community buildings such as schools and medical clinics. They then plan to scale the project across the country through partnerships with NGOs, national and county-level governments.

Related content

Creating cooler buildings in Dhaka - Million Cool Roofs Challenge


Bringing passive cooling to communities in Niger


What do cooler communities mean for a world facing a pandemic?


Tackling heat stress through cool roof solutions


The team

Constance Agyeman

Director of International Development

Maddy Kavanagh

Programme Manager, Longitude Explorer Prize

Olivier Usher

Head of Research

Similar Challenges

Big Green Challenge

Supporting community-led responses to climate change

Climate Smart Cities Challenge

An open call to cities who want to work with us to reduce greenhouse gas emissions

UNDP Renewable Energy Prize

Seeking renewable energy solutions for families in rural Bosnia and Herzegovina