The air duct calculator, or “ductulator,” is a commonly used tool for designing and installing duct systems. Unfortunately, many designers and technicians receive limited instructions on its correct use. This lack of instruction frequently results in duct systems that fail to perform as intended.
It’s typical to find that delivered airflow into a home is less than 65 percent of what’s required. In addition to low airflow, common problems include: excessive total external static pressure (TESP), ongoing equipment problems, nagging discomfort, thermostat wars, costly callbacks, and increased warranty costs. Let’s look at how four incorrect uses of an air duct calculator can contribute to these problems.