The Life-Saving Bathhouse is the world’s first senior-friendly bathhouse designed to prevent heat shock—the leading cause of bath-related fatalities among the elderly. It significantly reduced the number of fatal accidents in baths not only through spatial innovations but also with elder-focused design. Key spatial solutions include a Tea Bar to help raise body temperature before bathing, a Warm-Up Zone to maintain stable body temperature, and a Rest Reminder Bell that rings every 10 minutes to prevent prolonged bathing. Additionally, features of traditional bathhouses that overlooked senior users were redesigned with their needs in mind. These include senior-friendly tile colors, optimized wall heights for quick emergency response, and edgeless designs for improved safety. The entire construction process and strategy have been made open-source, enabling future bathhouses to adopt these safety measures to build safe spaces that prevent heat shock.