Ancient Mediterranean cooling techniques could help British homes cope with rising temperatures, according to an architect who co-wrote a book on natural cooling. As London's climate increasingly resembles that of Marseille, simple measures such as painting roofs white and using shutters are gaining relevance.
White surfaces reflect sunlight, reducing internal temperatures by 1°C to over 4°C, and can lower outdoor temperatures by up to 2°C. This helps counter the urban heat island effect, where cities become hotter than surrounding areas due to heat-absorbing materials.
However, effectiveness depends on combining strategies. For instance, white roofs work best when windows are kept shut during the hottest hours, with shutters or external shades blocking the sun. Heavyweight walls and floors, which store coolness from night air, also enhance comfort.
Night-time ventilation is crucial, but only if outdoor air cools after dark. In cities with strong heat island effects, reflective roofs and avoiding waste heat from air conditioning become even more important. Concerns about white roofs making homes colder in winter are minimal, especially with good insulation.
Costs vary: painting a house white is relatively inexpensive, while replacing dark tiles with reflective clay tiles costs from about £125 per square metre in the UK. The architect concludes that simple, low-tech solutions can help keep homes cooler and cheaper to run as the climate changes.
