Japan is deploying a 0.2mm-thick cooling sheet called Space Cool to lower surface temperatures on roofs and outdoor facilities [1].
The technology arrives as extreme heat threatens public safety and exceeds the operational limits of standard cooling systems. Conventional air conditioners are rated for external temperatures up to 43°C [1], making them less effective during the severe heat waves currently hitting the region.
The rollout is concentrated in the Tokai region, specifically in Kuwana, Mie Prefecture, and Mino, Gifu Prefecture [2]. These areas have faced intense conditions, including a period where temperatures reached or exceeded 40°C for three consecutive days [1]. On July 24, the country experienced a nationwide "kokusho-bi," or extremely hot day [1].
Takashi Hōshūzan, co-founder of Space School, said the material provides a zero-energy solution by neutralizing the heat gain from sunlight without requiring electricity [1]. Because the sheets are thin and simple to apply, they can be used on various outdoor structures and at public events, such as the Tenjin Festival in the Kansai region [2].
The urgency of such measures is echoed by local vendors struggling with the climate. A cake-stall owner said, "It's hot, hot. I'm really troubled if it's this hot" [1].
By reflecting solar radiation, the Space Cool sheets aim to reduce the reliance on power-hungry cooling systems that can struggle or fail when ambient temperatures spike [1]. The material's thin profile allows for rapid installation across wide surface areas, providing an immediate buffer against the sun's intensity [1, 2].
“"Zero energy (without using electricity), it is a material that can cancel out the heat input from sunlight, so you just stick it on."”
The adoption of passive cooling materials like Space Cool highlights a critical gap in urban infrastructure as climate patterns shift. When ambient temperatures approach or exceed the 43°C design limit of standard HVAC systems, mechanical cooling becomes unreliable. Shifting toward zero-energy, reflective materials reduces the load on the electrical grid and provides a necessary fail-safe for public health in outdoor spaces where air conditioning is impossible.
