Whilst freeze drying is known by its high energy requirements, few studies have been conducted assessing the efficiency of freeze dryers, specially related pharmaceuticals. A quantitative analysis is conducted on a batch freeze dryer used for biopharmaceuticals, aiming to know the process efficiency and to identify the components having the highest resource consumption as well as factors for potential improvement. Exergy and energy analysis were done combining experimental and modeled data. The process showed a task efficiency lower than 1%. This value is influenced by the low coefficient of performance of the refrigeration cycle as well as the large mass of steal in the device which is heated up and cooled down throughout the process.