The physics behind the map

Why some roofs run 15 °C cooler

Look at the map closely and you'll see it everywhere: two identical buildings, same street, same sun — and ten degrees between their roofs. The difference isn't luck. It's what the roof surface does with sunlight.

Absorb or reflect

A dark roof absorbs up to 90% of the solar energy hitting it and turns it into heat — that's how a 42 °C afternoon produces a 70 °C roof. A highly reflective ("cool") surface bounces most of that energy back to the sky before it ever becomes heat. The physical measure is SRI — Solar Reflectance Index: the higher, the cooler the surface stays.

What it changes indoors

Roof heat doesn't stay on the roof. It soaks through the slab and becomes air-conditioning load — in Gulf climates the roof can drive a significant share of a single-storey building's cooling bill. A cooler roof means cooler ceilings, less AC runtime, lower DEWA bills, and equipment on the roof (chillers, ducts) working in gentler conditions.

What the city says

Dubai's own green-building code, Al Sa'fat, sets a minimum roof solar reflectance (SRI ≥ 78 for flat roofs, clause 304.01) precisely to fight the urban heat island effect — the phenomenon this map makes visible. Reflective roofs aren't a gadget; they're written into how the city wants to be built.

How it's done in practice

Existing roofs don't need replacing. A liquid-applied reflective coating goes over the current surface — concrete, metal or membrane — and turns it into a cool roof in a day or two, while also sealing it against leaks. Typical measured drop in surface temperature: 15–20 °C at peak.

See it on the map

Switch the map to Lens mode and sweep across any industrial district: the coolest large roofs you'll find are almost always white or coated ones. The gap between them and their dark neighbours is the entire argument, measured from space.

Check your own roof

Search your building on the map — the card shows its measured morning temperature and the estimated afternoon peak. The dashed green line is what the same roof would look like with a reflective surface.