By Sohaib Shams
A traditional Chinese heating system used for over 2,000 years could provide insights for modern low-energy home heating, according to a researcher who grew up with the technology. The "kang" – a heated platform-bed made of earth bricks – warms only the sleeping surface rather than entire rooms, using residual heat from cooking fires.
A 2,000-Year-Old Heating System
In Harbin, northeast China, where winter temperatures regularly drop to -30°C, the kang has been a household staple. The system consists of a thick, raised slab connected to a kitchen stove. When the stove is lit for cooking, hot air travels through passages beneath the kang, warming its mass. The heated surface then radiates warmth for hours, allowing occupants to stay comfortable with thick blankets while the room itself remains cold.
Efficiency and Practicality
Unlike central heating that warms air throughout a home, the kang targets heat directly to where people sleep or sit. Its hundreds of kilograms of compacted earth release heat slowly, requiring no radiators, pumps, or fossil fuels beyond what is needed for cooking. Maintenance involves careful fuel management and ventilation to avoid carbon monoxide risks, but the system delivers long-lasting warmth with minimal energy input.
Lessons for Modern Energy Challenges
Yangang Xing, an associate professor of architecture and construction at Nottingham Trent University, argues that such traditional approaches deserve attention as energy bills rise and climate change makes winters more volatile. Heating only occupied spaces and keeping heat close to the body aligns with principles seen across East Asia, including Japanese kotatsu and Korean ondol systems.
Similar Traditions Across East Asia
Across the region, cold-weather adaptations evolved around heating people rather than spaces. These methods share a focus on localized warmth and fuel efficiency, offering potential models for reducing household energy consumption in colder climates worldwide.
