A design-oriented framework for smart home energy management system interfaces to support energy-saving occupant behavior

As smart home energy management systems (SHEMS) become increasingly common in residential buildings, there is a growing need for interfaces that move beyond passive energy reporting to actively support energy-saving occupant behavior. However, many existing SHEMS interfaces remain technology-driven and often overlook the cognitive processes and interaction mechanisms that shape user understanding, engagement, and decision-making. As a result, energy feedback and control features frequently fail to translate into sustained behavioral change. This study proposes a design-oriented framework for SHEMS interfaces that explicitly connects functional requirements with usability considerations. The framework is grounded in five core interface functions: Information Delivery, Real-Time Feedback, Personal Motivation, Control Flexibility, and Social Comparison. These functions were systematically derived using Abstraction Hierarchy (AH) from cognitive systems engineering, which enables structured reasoning from high-level system purposes and user intentions to generalized functions and concrete interface elements. To guide how these functions should be realized in interaction design, Norman's Design Principles were adopted as a usability-focused foundation and reformulated as explicit usability goals. The integration of AH-based functional modeling and usability goals results in a function-usability matrix that yields 30 actionable design guidelines. This matrix supports both forward interface design and diagnostic evaluation by maintaining traceability between user goals, system functions, and interaction design decisions. To demonstrate practical applicability, a five-function SHEMS interface prototype was developed. The prototype illustrates how the proposed framework can be instantiated in concrete interface layouts that support awareness, interpretation, motivation, and user control within a unified system, serving as a design-oriented demonstration rather than an empirical evaluation. Overall, this study contributes to human-building interaction research by offering a replicable, design-oriented methodology for developing SHEMS interfaces that are cognitively aligned, usable, and supportive of energy-saving behavior in residential contexts.