A volunteered geographic information (VGI) tool is built into the HEAT project so that participants can identify roof materials for homes in their neighbourhood or city (Fig 10). This will allow the HEAT team to define ‘true’ kinetic temperatures which are used to determine the waste heat and HEAT Score for every home in the city. VGI defined roof materials will also be validated against a roof material classification based on detailed colour and near-infrared airborne images, and MLS information. When the roof material is selected for a home, a yellow tick mark is shown to confirm your contribution. This means that your roof material selection will be reviewed by the HEAT team. A green tick mark means that the roof material is defined the same by both volunteers and MLS while a grey tick mark means that the roof material defined by volunteers does not match with MLS.