The Science of Comfort - Price Industries HVAC blog

What Is a Drop Box?

Written by Ryan Compton | March 18, 2025 at 2:00 PM

A Simple Approach to Air Distribution for Large Spaces

In the world of air distribution, a drop box is a plenum with multiple air outlets that is connected directly to an air handling unit (AHU) by a short run of ductwork. A drop box can be an effective way to deliver a substantial volume of conditioned air to large, enclosed spaces.

Price’s Drop Box with High-Capacity Drum Louvers with adjustable four-way (left) and six-way (right) airflow patterns

Typically located directly below an AHU, the drop box is usually equipped with four to six air outlets that distribute air equally in all directions. Since the duct run between the AHU and drop box is short and the air volumes are large, turbulence and air velocities can be high. A well-designed drop box will have sturdy construction to handle these conditions and optimized internal geometries to minimize any turbulence. This ensures that airflow can be effectively distributed while keeping pressure drop and self-generated noise to a minimum.

It is common for drop boxes to use high-capacity drum louvers as their air outlets. These robust devices are already designed for large air volumes and have adjustable blades to control airflow patterns horizontally and a rotatable drum to adjust airflow patterns vertically. This provides flexibility to fine-tune airflow patterns to achieve excellent air distribution for different spaces and operating conditions.

Drop boxes are ideal for large, enclosed spaces such as manufacturing plants

With long throws and minimal ductwork, drop boxes are a simple and cost-effective solution for a variety of applications, including warehouses, large retail stores and manufacturing facilities

For more information about how you can use drop boxes in your next project, check out our brochure or contact our team at GRD@priceindustries.com.

 

Ryan Compton is Application Engineering Manager for Price's GRD team. He is based out of Price's headquarters in Winnipeg, MB. Click here to connect with him on LinkedIn.