The rapid expansion of digital technology presents environmental challenges, emphasizing the significance of sustainable web design in achieving the United Nations' Sustainable Development Goals by 2030. This study examines the impact of implementing web sustainability guidelines and introducing an eco mode on user experience, aiming to explore a sustainable alternative. It examines the impact on user experience, particularly in terms of first impressions, credibility, and motivation. Utilizing a comparative analysis employing both quantitative and qualitative methods, user experiences were assessed through a web survey using the AttrakDiff tool, supplemented by both open and closed questionnaires. The results suggest that eco mode can enhance sustainability but may have mixed effects on user satisfaction. While users generally responded positively to designs with lower resource consumption, some expressed concerns regarding diminished aesthetics and inspiration. Thoughtful implementation of sustainable web design can enhance user experience by striking a balance between sustainability and usability. This research contributes to understanding effective sustainable practices in web design and sets a foundation for future studies on their implementation.