Japan have begun installing solar-powered heaters that store sunlight during the day and release gentle warmth throughout the night, offering life-saving relief to people experiencing homelessness during freezing winter conditions.
The innovative heaters which are being tested in public parks, benches, shelters and underpasses in major cities like Tokyo and Osaka use phase-change materials (PCMs) that absorb solar energy as heat during daylight hours and slowly radiate it back when temperatures drop after sunset. This entirely off-grid system works without any electricity or fuel, providing up to 10–12 hours of steady warmth in conditions where traditional shelters and outdoor rest spots would otherwise be dangerously cold.
What makes these devices particularly inspiring is not just their eco-friendly design but also their humanitarian impact. Installed in areas frequented by people without stable housing, the solar heaters create pockets of warmth and safety, helping reduce cold-related health emergencies and offering dignity to individuals in need during harsh winter nights.
The systems are designed to be affordable, weather-resistant and maintenance-free, and volunteers and urban planners are exploring installations that include USB charging points and lighting, turning public benches, bus shelters and resting spots into multi-use support stations for vulnerable populations.
As winter approaches and climate extremes become more frequent, Japan’s solar-heated public infrastructure serves as a model of renewable energy meeting social welfare a reminder that sustainable technology can also be a force for empathy and inclusion.
