Cool roofs reflect the sun’s heat and emit absorbed radiation back into the atmosphere at a higher rate than standard materials. They reduce the amount of heat held and transferred to the building below, keep the building cooler and at a more constant temperature.
Cool roofs have additives to the base material or paint. A simple analogy is a black car compared to a white car. On a sunny day, the white car will be cooler to touch than the equivalent black car.
The benefits of cool roofs include:
- reducing utility bills associated with air conditioning
- increasing occupant comfort by reducing the amount of air conditioners installed
- lower roof maintenance costs
- extending roof life, which avoids re-roofing costs and reduces solid waste
- reducing the amount of heat absorbed and held your city, known as the urban heat island effect
- increasing ecological sustainability factor, or making your building 'greener'
The City of Melbourne is committed to achieving zero net emissions for our city by 2020. A key step in meeting this goal is reducing the amount of energy used to cool the city’s buildings.
Though our 1200 Buildings Program we aim to encourage and support building owners, managers and facility managers to improve the energy efficiency of commercial buildings in the municipality of Melbourne. Cool roofs could be applied to many buildings in the city to enhance their energy efficiency.
The urban heat island effect
This is often seen in urban areas, where infrastructure absorbs, maintains and then reradiates heat. This causes inner city areas to often be a number of degrees hotter than surrounding rural areas.
Through the use of cool roof products, Melbourne can decrease the impact of the urban heat island effect on our city. Designing our infrastructure to minimise heat absorption will make Melbourne more resilient to increasingly extreme heat conditions as the climate changes.
The City of Melbourne in 2011 commissioned the University of Melbourne to research how different cool roof products perform in Melbourne’s climate. The results of this research can be used to identify buildings where the installation of a cool roof would be beneficial.
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