Flow hoods are usually compensated for which factor?

Flow hoods are primarily designed to measure and balance airflow in HVAC systems, and one of the critical compensations they make is for back pressure. In ducted systems, back pressure can occur due to various factors such as duct fittings, obstructions, or the resistance posed by filters.

When measuring airflow, it's essential for the flow hood to account for this back pressure to provide an accurate reading of the air delivered by the system. If back pressure is not compensated for, it could lead to misleading airflow results, potentially affecting system performance and efficiency.

By adjusting for back pressure, flow hoods ensure that the readings reflect the true operational conditions within the ductwork, allowing technicians to make informed decisions regarding system adjustments, repairs, or maintenance.