Which method is commonly used to check airflow across a coil in HVAC systems?

The correct method commonly used to check airflow across a coil in HVAC systems is an airflow hood. An airflow hood, also known as a flow measurement hood, is specifically designed to measure the volume of air flowing through a grill, register, or duct. This device captures the airflow as it exits or enters the coil, giving technicians precise measurements in cubic feet per minute (CFM). This accuracy is essential for ensuring the system operates efficiently and meets design specifications.

Utilizing an airflow hood allows for direct measurement, making it a practical tool for diagnosing performance issues in HVAC systems. It can help ensure that the coil is receiving the proper amount of airflow, which is crucial for effective heating and cooling.

In contrast, volumetric flow measurement can be used in various contexts but does not provide the same level of convenience and accuracy as an airflow hood in an HVAC setting. Anecdotal estimation lacks the precision needed for effective diagnostics, relying instead on subjective assessment rather than quantifiable data. The temperature differential method involves assessing the change in temperature across the coil rather than directly measuring the airflow itself, which does not provide the same comprehensive evaluation of air movement.