British engineer Tom Greenhill has proposed a low-cost, low-energy solution for keeping UK homes cool in a heatwave: painting the outside of windows with yoghurt.
Painted on with a roller, yoghurt dries quickly and creates a fritted glass-like effect that Greenhill says should reflect light and heat in much the same way as other energy-efficient window coating products.
Greenhill admits that this may seem like a "totally eccentric idea". But based on his own experiments, he is yet to see a downside to the strategy.