This paper explores the use of proxies for energy efficiency in teaching energy-optimized WordPress components to future software developers in a 7th-semester Web Development course. Specifically, we examine the relationship between the concept “less work requires less energy” and its practical application as “fewer lines of code require less energy.” Our study evaluates two key aspects: (1) the effectiveness of lines of code (LOC) as a proxy for energy consumption in web development, and (2) the accessibility of this proxy for guiding students in creating energy-efficient WordPress components. The evaluation is based on empirical data from student project submissions and survey feedback on their experiences with energy-aware programming, providing insights into both learning outcomes and the feasibility of integrating sustainability into software engineering education.