Coway said Thursday it ranked first in four categories of the 2026 National Customer Satisfaction Index. The annual index, compiled by the Korea Productivity Center, measures customer satisfaction based on surveys of actual product and service users. Coway topped the rankings in water purifiers, mattresses, healthcare massage appliances and rental care services. The company retained its No. 1 position in the water purifier category for a third consecutive year, led by its Icon Ice Water Purifier