Updated: Jul 4, 2020
What is the difference between grade and quality? A grade is a design intent. It consists of features or capabilities of a product. The categorization of a product into different grades is based on its features and functionality.
For example, there are datacenter-grade air conditioning units (similar in size to a large refrigerator). There are also room-cooling grade air-conditioners (portable and about the size of a microwave oven). These are not meant for small network rooms or telecom closets. Attributes such as cooling capacity and size of these two grades of air-conditioners are different. You need to identify and purchase a grade of equipment that meets your requirements.
Good quality, on the other hand, is about being defect-free and easy to operate and manage and one that provides a good user experience. Quality aspects are not about features or functionalities. Problems related to quality create inconvenience and difficulty for users.
Products in a higher grade could be of low quality. Products in a lower grade could be of high quality.