This study examined the impact of energy-efficient building practices on the operational performance of star-ratedhotels in Nairobi City County, Kenya. Hotels are among the most energy-intensive commercial establishments,incurring high operational costs largely driven by lighting, heating, ventilation, and air conditioning (HVAC)systems. The study adopted a descriptive correlational cross-sectional design on 49 star-rated hotels in NairobiCounty. Operational managers were purposively selected as respondents because of their direct involvement inimplementing and monitoring sustainability practices. Data was collected through structured questionnaires. Bothdescriptive and inferential statistics were run in the analysis of data. The findings reveal a moderate but consistentadoption of energy-efficient practices such as LED lighting, smart HVAC systems, renewable energy integration,and staff training on sustainable energy use. Hotels reported noticeable reductions in monthly utility bills andoverall energy costs. Regression analysis revealed a moderately strong, statistically significant relationshipbetween energy-efficient practices and energy costs (R = .620, R² = .384, p < .001). This implies thatapproximately 38% of the variation in energy costs savings can be explained by the extent of energy efficiencyadoption. It can be concluded that energy-efficient building practices significantly contribute to cost savings instar-rated hotels. Hotels should prioritize investment in modern HVAC technologies, energy monitoring systems,and renewable energy sources to enhance sustainability and reduce operational costs