How white roofs can help buildings beat the heat

In Greece's Cyclades, the roofs of the famous whitewashed houses that cling to the cliffs also have a white finish. Photo: AFP Oia, Santorini, Greece - AUGUST 26, 2015: Man stays on the white roof of hotel and paints it with big swab and speaking mobile phone.

Paint the roof of a building white to reduce the heat inside. It sounds so simple, yet this practice is still far from systematically applied.

Known as a cool roof, this method is by no means new, but it's becoming more and more popular in many countries as heat waves become more frequent and intense.