The individual air-conditioning is getting popular as dog days return.

What started as a niche invention two decades ago has become one of Japan’s most successful and eco-conscious answers to extreme summer heat. While the concept of air-conditioned clothing had existed in patents for years, it was former Sony engineer Hiroshi Ichigaya who turned it into a viable business.

His innovation, known as the fan jacket, not only keeps people cool but also helps reduce electricity consumption and environmental damage.

Ichigaya founded his company, Kuchofuku, in 2004 with the idea of creating personal cooling systems for people working in environments where traditional air conditioning is impractical, such as construction sites, tunnels, and open-air fields.

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After years of refinement, Kuchofuku’s jackets — with two lightweight electric fans embedded in the lower back — create a continuous breeze around the body, enhancing sweat evaporation and significantly lowering skin temperature.

Practical cooling, personal comfort

Unlike traditional air conditioners that cool ambient air, fan jackets work by amplifying the body’s natural cooling system. The twin fans, about 10 centimeters in diameter, draw in outside air and circulate it under the jacket to evaporate sweat and cool the skin directly. This creates a personal microclimate that’s both effective and energy-efficient.

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They key technical features of the Kuchofuku Fan-Cooled Casual Jacket, which is 100% waterproof polyester, include two built-in fans with five speed settings; rechargeable waterproof lithium-ion batteries ranging from 6V to 14.4V, battery life of up to 17 hours (at 6V), depending on voltage level; velcro fasteners, one breast pocket, and two hand-warmer side pockets. The jackets are available in sizes from M to 5L.

A full-set jacket - which also comes with wired controller, AC adapter, fan cables, and pouch - typically costs between $40 and $100.

Design-wise, the jackets blend in seamlessly with casual wear. Available in silver, black, and light blue, they look like regular outerwear until you notice the gentle hum of fans working quietly in the background.

As heatwaves grow more frequent and intense, wearable cooling technologies are setting an example in sustainable personal comfort and environmentally-friendly solutions in an increasingly warming world. Global interest in wearable cooling technology is growing, too, especially as climate change intensifies summer heatwaves, opening the door for broader international adoption.

Kuchofuku was founded in 2004 and has since licensed its technology to multiple companies, including major firms like Makita, which began producing fan jackets in 2015.