Airflow measurement on all-profile vents-KIMO instruments China

Optimum and appropriate techniques

Measuring the airflow rate through a building's air vents, grilles and diffusers helps to ensure thermal comfort, control the air change rate for indoor air quality and optimise the ventilation system's energy efficiency.

This applies to all types of buildings, whether residential, commercial or industrial, and also for safety reasons (smoke extraction, etc.). Whatever the method (scanning, zoning or cone measurement), the measurements must be taken with instruments adapted to the different types of air vents.

Parameters to be monitored

Airflow and air velocity

SCANNING METHOD

ZONING METHOD

CONE MEASUREMENT

METROLOGICAL SERVICES

SCANNING METHOD

On small flat grilles with straight airflow, scanning consists of placing a propeller probe 2 cm from the grille and sweeping across its entire supply or exhaust surface. The average flow rate is then calculated over a given period of time.
For optimum grid measurement using the scanning technique, we recommend using helix probes with a diameter of 100 mm. They provide fast, accurate results, particularly on large grids. Sauermann offers a wide range of propeller anemometers such as the Kimo AMI310.

SCANNING METHOD

Vane Thermo-anemometer with integrated vane probe

Si-VV3

Thermo-anemometer with integrated vane probe

LV 110 / 111 / 117

Multifunction

AMI 310

ZONING METHOD

For flat grids with unidirectional flow, the zoning technique (or point-by-point averaging) is also used. This involves dividing the cross-section of the grid into zones and averaging the flow rates in each zone to derive an overall result.
The most reliable values combine average measurements for each zone over the same period of time. The choice of probe depends on the application, but for very low-speed airflows requiring high sensitivity and accuracy, a hot-wire probe is recommended.

ZONING METHOD

Hotwire thermo-anemometer

VT 110 / VT 115

Thermo-hygrometer-anemometer

VT 210

CONE MEASUREMENT

Using a cone of the right size will improve efficiency and accuracy. For diffusers larger than 450x450 mm, a balometer is more versatile and specialised. This equipment is essential for multidirectional flow diffusers.
Applying a cone interferes with the airflow by generating turbulence. Our anemometers can compensate for the generated pressure drop by selecting the type of cone in their menu. For balometer measurements, this compensation is achieved by selecting the vent profile on the mobile application.

CONE MEASUREMENT

Airflow cones

K35 - K75 - K120 - K150

Airflow cones

Si-K25 - Si-K85

Air Flow Meter

DBM 620

METROLOGICAL SERVICES

Whatever the technique or type of probe used to measure airflow, the sensors are subject to physical constraints. They need to be calibrated frequently to guarantee reliable measurements - every year at best.
At Sauermann, we calibrate your anemometers and balometers in our laboratories in the Dordogne. The operation takes place in areas equipped with state-of-the-art speed benches for maximum accuracy and compliance with standards.

Blog posts

2026-6-27 Measuring air flow rate at an air vent: getting it right
Air vent measurement is no easy task. It requires different methods and instruments depending on the type of vent in question. Following the tips in this article will ensure you get your measurements right.
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2026-6-27 Using CO2 concentration to measure air change rate
Air change rate (ACR) has always been a key concept in building ventilation system management. But now, it’s become even more important – as a vital measurement in the fight against COVID-19, and against bacteria and viruses more generally.
Instruments

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