Cool roofs provide numerous benefits that contribute to the health of a community, to the occupants of the building and to the owner’s pocket book. Compared to traditional flat roofing applications such as tar and gravel flat roofs, cool roofs use materials that help reduce GHG emissions, save money on air-conditioning costs, and improve air overall quality. When enough are installed on a citywide scale, cool roofs can also reduce the urban heat island effect—helping to lower temperatures across whole urban communities.
These potential benefits have been recognized for many years, and cool roofs are already being mandated under certain conditions as an energy efficiency measure. In Toronto, for example, the city mandates the construction of cool or green roofs on new commercial, industrial, institutional and residential development.
Cool roofs are distinguished among energy conservation measures because of the many environmental benefits they can provide. A crucial benefit of cool roofs is their ability to help mitigate the urban heat island effect. Cool roofs help improve urban conditions by:
- Contributing to cooler ambient temperatures by immediately reflecting solar radiation back into the atmosphere before it can degrade to heat, as well as re-emitting a portion of infrared light.
- Indirectly reducing air-conditioning use by lowering the ambient air temperatures.
- Improving grid stability and increasing peak energy savings by reducing the need for air-conditioning at the hottest times of the year.
Although many cool roofs are light-coloured or white, they are increasingly being created in a range of colours and patterns and can look nearly identical to traditional roofing materials.