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testo 405 - Thermal Anemometer

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The testo 405 thermal anemometer is for precise air velocity, volumetric flow, and temperature measurements in ducts and indoor environments – ideal for HVAC spot checks and draft detection.
  • Highly accurate – at low air speeds (especially from 0 to 2 m/s).
  • Measures – air velocity, volumetric flow, and air temperature.
  • Integrated protective cap – for sensor protection.
  • Extendible telescope up to 300 mm – ideal for duct measurements.
The testo 405 thermal anemometer is a compact, highly precise thermal anemometer designed for quick and reliable measurements of air velocity, volumetric flow, and air temperature. Whether you're conducting HVAC spot checks in ventilation ducts or identifying air drafts in indoor spaces, the testo 405 is an essential tool.

The permanently attached extendable telescope (up to 300 mm) makes it perfect for reaching into narrow ducts, while the swivelling, backlit display ensures that your readings are always easy to read, even in awkward positions. For added convenience and accuracy, the testo 405 comes with a mounting bracket for optimal placement in ducts.

One of its standout features is its high level of precision in the low-speed range (0 to 2 m/s), making it especially suitable for detecting drafts near windows or poorly insulated areas. When not in use, the built-in rotating protective cap safeguards the sensitive sensor.

Temperature - NTC

Measuring range
-20 to +50 °C
Accuracy
±0.5 °C
Resolution
0.1 °C

Velocity -Thermal anemometer

Measuring range
0 to 99990 m³/h
0 to 5 m/s (-20 to 0 °C)
0 to 10 m/s (0 to +50 °C)
Accuracy
±(0.3 m/s + 5 % of mv) (Remaining Range)
±(0.1 m/s + 5 % of mv) (0 to 2 m/s)
Resolution
0.01 m/s

General technical data

Weight
115 g (with batteries, without packaging)
Dimensions
490 x 37 x 36 mm
Operating temperature
0 to +50 °C
Battery type
3 AAA micro batteries
Battery life
Approx. 20 h
Display type
LCD (Liquid Crystal Display)
Length probe shaft
300 mm
Diameter probe shaft
16 mm
Diameter probe shaft tip
12 mm
Storage temperature
-20 to +70 °C

testo 405 - Thermal Anemometer, duct holder and batteries

Measurement of indoor air velocity

For workers to feel comfortable in their indoor working environments, "thermal comfort" has to prevail. The EN 13779 describes this as a state that prevails when people are satisfied with the air temperature, humidity, air movement and thermal radiation in a room, and require neither hotter, colder, nor drier or more humid indoor air.

The testo 405 is particularly well suited to measuring indoor flow velocity. Low air velocities, such as at draughty windows, can therefore be precisely located and measured extremely accurately.

Measurement in ventilation ducts

Observance of air flows in the ventilation duct is of utmost importance for the function of the ventilation and air conditioning system. If the air flows are smaller than intended, the removal of room loads (heating, cooling and substance loads) may not be ensured in certain circumstances. Therefore, the most accurate recording of air flows as possible is particularly important.

Our thermal anemometer testo 405 allows particularly cost-effective measurement of low air velocities. It enables the accurate and parallel measurement of air flow, volumetric flow and temperature. The extendible telescope allows measurement at a depth of up to 300 mm.

The display can be swivelled into various positions, enabling optimum measurement readout.

Contact Us
Testo Ltd
Newman Lane
GU34 2URAlton
HampshireUnited Kingdom
01420 544433

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