Pre Cooling Air Unit ( PAU )

A Pre-Cooling Air Unit (PAU)—also known as a Primary Air Unit in HVAC terminology—is a specialized ventilation system designed to pre-treat outdoor fresh air before it reaches the main Air Handling Unit (AHU). The PAU typically performs initial filtration, dehumidification, and slight cooling of the incoming air, preparing it for more efficient conditioning by the AHU. Unlike a full-fledged cooling system, the PAU focuses on air quality and pre-conditioning, especially in environments where outdoor air intake is high.

PAU systems are particularly valuable in extreme climate conditions and are widely used in commercial, industrial, and institutional buildings. By handling the initial air treatment load, the PAU reduces the energy burden on the AHU, resulting in improved efficiency and lower operational costs. These units are generally constructed in two types: Roof-Top (Ceiling Suspended Ducted) Units for compact installations, and Floor-Mounted Units that can be tailored to meet specific airflow and treatment requirements.