Airflow Capture Hood - Balometer

Airflow Capture Hood - Balometer

An airflow capture hood or balometer is a device used for measuring the volume of air coming out of grilles and diffusers in HVAC systems. “Balometer” is actually a term coined by Alnor in 1983 that has become synonymous with “airflow capture hood” today. Before the invention of this technology these measurements were typically made with a deflecting vane anemometer and the appropriate diffuser probe. These types on anemometers required that the technician apply the correct A_k, or area factors specific to each grille manufacturer. An airflow capture hood allows the user to take measurements much more quickly and easily because it uses a one-step, direct volume measurement that doesn’t require area factors.

The fabric skirt and frame of an airflow capture hood can be found in a variety of sizes to fit different grilles and diffusers. Most units, such as those from Kanomax and TSI/Alnor, allow for interchangeability of the fabric skirt and frame. Spare skirts and frames are available in various sizes. There are also units specifically designed for very low airflow volumes, such as the LoFlo series from TSI/Alnor. Both analog and digital instruments are available.