In this episode of the HVAC Know It All Podcast, host Gary McCreadie is joined by Eric Ruggles, Director of Engineering at Ritchie Engineering Co., Inc. (YELLOW JACKET), to discuss the key differences between airflow and static pressure and how to measure both correctly. Eric explains how airflow is calculated using air velocity and duct size, while static pressure is measured across system components to understand system performance. The conversation covers tools like hot wire anemometers and manometers, along with proper testing methods such as duct traversing and pressure tip placement. Gary and Eric also explore common issues like high static pressure caused by poor duct design, dirty filters, or oversized equipment, and how these problems can impact overall system efficiency.

In this conversation, Eric explains the differences between airflow and static pressure in HVAC systems and how each one is measured. He describes how airflow is based on air speed and duct size, while static pressure shows how much resistance the system has. Eric and Gary discuss tools like hot wire anemometers and manometers, along with proper testing methods such as duct traversing and pressure tip placement. They also cover how issues like dirty filters, poor duct design, and system restrictions can raise static pressure and reduce overall system performance and airflow.

Expect to Learn:

How airflow and static pressure differ and why both matter in HVAC systems.
How to use tools like hot wire anemometers and manometers for proper testing.
How duct traversing helps get accurate airflow measurements.
How static pressure testing can identify restrictions in filters and ductwork.
How issues like dirty filters, poor duct design, and closed vents affect system performance.

Episode Highlights:

[00:00] - Sponsor Ad: Factory Direct Filters

[00:42] - Intro to Eric Ruggles in Part 1

[02:34] - Static pressure and airflow are different, and need different tools

[04:18] - Eric: Air speed units (ft/min, m/s) & calculating volume

[07:15] - Hot wire anemometer: traverse duct, app calculates CFM

[10:56] - Static pressure: positive on supply, negative on return

[16:48] - Total external static: check return & supply sides separately

[19:42] - Remove filter to test restriction; 1" high-MERV vs. 5" filter

[23:61] - Plugging vents raises static, harms the system

This Episode is Kindly Sponsored by:

Cintas: https://www.cintas.com/hvacknowitall