Flow Hoods: What Are They & Why Do We Use Them?

Do you ever wonder what that funny looking cone is we put up to the ceiling when we’re balancing a store? We get asked all the time! (And no, it's not for cleaning the ducts or checking for ghosts.) It's a flow hood, a critical testing instrument we use.

A flow hood is a portable test instrument that measures volumetric airflow through grilles, diffusers, and registers. The hood can be aligned with a diffuser and uses the measured velocity to determine the total volume of airflow being discharged through that diffuser. This volume is measured in CFM, or cubic feet per minute.

Hoods come in many styles and there are several different manufacturers, including Dwyer, Evergreen, and Alnor. NTi uses the flow hood to measure the total volume of air flowing through an HVAC system or within a particular component of the system. This could be an exhaust fan, air handler, rooftop unit, or any other HVAC unit. In some situations, a flow hood will be utilized in combination with other measuring methods to determine the total volume of airflow moving through a system.

Each component of your building’s HVAC system is designed to move a specific range of airflow volume. It is vital that all equipment is performing within these designed ranges for peak efficiency and performance of the equipment. This allows the equipment to perform as it was designed and leads to a properly treated and comfortable space. A space that is unbalanced experiences issues like doors suctioning or blowing open, stained ceiling tiles, grease buildup, and issues with customer comfort.

We use the flow hood and other measuring devices to test each piece of equipment and balance each system within its designed parameters. When each component within your building is achieving the designed airflows and performing as designed, the building is "balanced." This leads to a comfortable space free from pressure issues!

Contact us to learn more: www.nationaltab.com/contact.