As product life cycles become shorter and shorter, stakes are higher in terms of sales and profits, making it an imperative for companies to enhance existing product families as much as possible. Redesigning a family of products can become a difficult task when considering the number of variables (products, modules, components, etc.), competing objectives (diversity-commonality, cost-variety, etc.), and actual technical solutions (cost value, architectural constraints), etc. In this paper, a methodology using the Design Structure Matrix flow (DSMflow,), Value Analysis (VA), and the Commonality versus Diversity Index (CDI) is proposed to improve an existing family of products. These three tools enable the assessment and the improvement of (1) commonality and diversity within the family, (2) feature satisfaction through design, and (3) definition of new modules/components and their interfaces. A case study based on a family of refrigerators (including CAD models) is detailed in this paper to demonstrate the methodology. The proposed methodology supports both the reengineering of an existing family and can also be extended to benefit the early development stages when designing a new family of products.