The hotel sector plays a vital role in the global economy, making a substantial contribution to employment and local economic development. However, it is also the second most energy-intensive segment of the tourism industry. Energy costs account for approximately 3% to 6% of hotel operating expenses and nearly 21% of the sector’s CO₂ emissions. As energy costs rise, environmental regulations become stricter, and consumer awareness of sustainability increases, there is growing pressure on hoteliers to implement energy-efficient measures and improve their environmental performance. This study investigates the integration of Internet of Things (IoT) technology and real-time energy data from smart meters to detect deviations in energy usage within hotel buildings. Specifically, it examines how these technologies can surpass the capabilities of traditional Building Management Systems (BMS) by identifying areas of excessive energy consumption. Energy data from 11 case study hotels in London were analysed to establish energy consumption patterns across different hotel categories and to identify areas of high-intensity energy use. A more detailed investigation was conducted in one selected hotel, where IoT-enabled smart metering was implemented. A year-over-year comparison of energy consumption revealed a 7.6% reduction in electricity use on the hotel’s main supply lines, resulting in a savings of 319.5 MWh and a decrease of 71.9 tons of CO₂ emissions. The findings highlight the potential of IoT-driven smart metering systems in optimising energy efficiency within the hospitality sector. By enabling real-time monitoring and more precise energy management, these technologies offer a viable pathway for hotels to improve sustainability, reduce operational costs, and comply with increasingly stringent environmental regulations.