This e-learning course introduces the fundamentals of demand-side Energy Efficiency (EE), emphasizing its importance for sustainable development. Participants will explore the key drivers and barriers that influence the adoption and implementation of EE measures. The course provides a clear understanding of the EE project cycle, a step-by-step framework for planning and executing effective initiatives. Through this structured approach, learners gain insights into how to design, manage, and evaluate EE projects. By the end, participants will be equipped with foundational knowledge to promote and implement EE solutions successfully.