90% of Japanese homes do not meet the WHO housing and health guidelines for a minimum room temperature of 18℃ in winter. Promotion of warm homes by improving thermal insulation performance during new construction and renovation is expected to have the effect of preventing chronic disease, reducing frail risk and long-term care. This article introduces medical evidence on housing and health based on the nationwide intervention survey for 2,000-household / 4,000-residrnts and other large-scale studies done by authors.