The textile industry has relatively high energy consumption compared to other small and medium industries. More energy performance studies are required to improve process energy efficiency. For any energy efficiency study, measuring the energy consumption quantitatively is the first step. This paper utilises high-resolution empirical energy data of a vertical case study textile mill to estimate its overall energy use and to find out any underlying efficiency improvement opportunities. Average seasonal load profiles have been calculated against shift patterns and weekly and annual consumption trends are investigated. Despite winters being at a time of off-peak production, heating related gas use was found to be significantly high during this period, with high specific energy consumption (SEC) per unit of production. The study identified some actionable energy saving opportunities that consisted of reducing the weekend baseline load for both electric and gas through behaviour change and simple management. Some site-specific processes and technology-based energy savings were also identified. The paper reveals how a more detailed energy analysis of a process-specific non-domestic building (such as a textile manufacturer) can provide much richer and actionable information than more standard energy audits and surveys. The key methods and techniques used in this analysis are outlined in the paper, such that they may be extrapolated to other non-domestic buildings in similar industries.