In this study, design evaluation guidelines for light interfaces of home appliances were derived. The light interface conveys a product's information to the user through light as a communication medium. Even though good light interfaces allow users to read a product's information regardless of ambient lights, poor light interfaces cause usability issues such as glare. Hence, this study figured out critical design features for the successful user experience with a light interface based on the literature review and the user research. In addition, evaluation methods and criteria for each item were also sorted for designers to evaluate the light interface objectively. Then, the guidelines were applied to the design practice of Coway corporation. Overall, the guidelines helped designers consider user experience thoroughly in the design process and improve the design quality through the evaluation. Finally, limitations and further studies are discussed to obtain more sophisticated guidelines for light interfaces of diverse appliances.