The HVAC commissioning engineer is first and foremost a field professional. Measuring instruments are an extension of their expertise: they make it possible to quantify, verify and prove that systems operate in line with the specification.
1. Hot-wire anemometer
Measures air velocity with high precision (0.01 m/s). Ideal for low velocities in ducts or rooms. The hot wire (tungsten or platinum) cools in proportion to the air velocity. Common brands: Testo 425, Kimo VT 210.
2. Vane anemometer
More robust than a hot-wire probe, it measures higher velocities (1 to 30 m/s). Available as a duct version (Ø 16 mm) or large-diameter version (Ø 100 mm) for grilles and diffusers. Indispensable for in-duct traverse measurements.
3. Flow hood (balometer)
The flow hood (or balometer) is the reference tool for measuring airflow directly at diffusers and terminals. It captures the entire airflow and displays it in m³/h. Typical accuracy: ±3%. Leading models: Testo 420, Swema 3000, Alnor EBT731.
4. Micromanometer
Measures very low differential pressures (0 to 2,500 Pa). Essential for checking filter pressure drops, static pressure in ducts and the setting of airflow regulators. The micromanometer has replaced the old inclined water-column manometer.
5. Hydronic balancing instrument
The hydronic balancing instrument (e.g. IMI TA-SCOPE or Caleffi DPH) connects to the pressure test points on balancing valves to measure flow rate, differential pressure and temperature. It is the key tool for hydronic balancing. It stores readings and generates reports automatically.
6. Multimeter
Measures voltage, current, resistance and continuity. Indispensable for diagnosing control circuits, checking 0-10V or 4-20mA signals on motorised valves and checking power supplies. A TRMS (True RMS) multimeter is recommended.
7. Thermal imaging camera
Shows temperature differences across terminal units, ductwork and electrical panels. It reveals insulation defects, leaks in pipework and ductwork, and thermal imbalances. Recommended resolution: at least 160×120 pixels (FLIR C5, Testo 868).
8. Infrared and contact thermometers
An IR thermometer measures surface temperature remotely. A contact thermometer (Pt100 probe or thermocouple) is more accurate for measurements on pipes and headers. The two complement each other on site.
9. Hygrometer
Measures relative humidity and air temperature. Essential for controlled environments (hospitals, data centres, museums) and for checking that humidifiers and dehumidifiers are working properly.
10. Sound level meter
Measures sound levels in dB(A). Increasingly required in specifications to check that HVAC systems comply with regulatory limits (NRA for housing, French labour code for offices). A class 2 sound level meter is sufficient for most measurements.
Tip: have your instruments calibrated once a year. An out-of-calibration instrument gives false confidence and can lead to disputes over commissioning reports.