1. Introduction
 2. Ondol (Gudul)
  2.1 The changes in Gudul (Ondol) heating system
  2.2 The problems of briquet Gudul heating system
  2.3 The transformation from traditional Gudul-goraesystem to hot water circulation floor heating system
  2.4 The architectural regulation for Gudul heating
  2.5 The architectural regulation for chimney
 3. Conclusion

• Chanhwan Choi(Dept. of Architectural Engineering at University of Seoul) Corresponding author
• June Bong Kim(Dept. of Architecture at Beijing Technology University)
• Chuloh Jung(Architecture, Graduate School of Techno Design at Kookmin University)