What Is an Anemometer?

Despite their tricky name, anemometers are surprisingly common tools.  If you are not absolutely sure what an anemometer is, then this article is for you!

Anemometer Definition

An anemometer is a device that measures wind speed, which makes these devices indispensable for a wide variety of applications.

The Main Types of Anemometer

There is an extensive selection of models of anemometer available at Instrument Choice. Each design has different properties and measurement methods suited to specific applications. Below, our scientists have detailed each of these types along with representative product examples.

Figure 1 Wind Vane

1. What Is a Vane Anemometer?

A vane anemometer measures wind speed via an impeller, propeller or turbine. A vane anemometer must be faced in the direction of the wind source to take a measurement; this forces the vane's blade to start spinning. The device measures each time the magnetised blade passes the reed switch within a specific timeframe and converts this to a windspeed measurement.

Vane Anemometer Applications:

Vane anemometers are a popular choice for;

• Various outdoor monitoring tasks, including; building sites and agricultural applications; and
• HVAC applications such as monitoring exhaust flow and exhaust hoods.

Product Example: TSI 5725 VelociCalc Rotating Vane Anemometer Product code: IC-5725   The professional VelociCalc Rotating Vane Anemometer accurately measures air velocity and temperature, calculates flow rate, performs averaging, and can determine minimum and maximum readings.   Wind measurement range: 0.25 to 30 m/s (50 to 6,000 ft/min) Accuracy: ± 1.0% of reading

Figure 2 Wind Cups

2. What Is a Cup Anemometer?

Cup anemometers generally consist of three cups attached to horizontal arms mounted on a vertical rod. As the wind velocity increases, the cups spin freely. Like vane anemometers, a sensor or reed switch measures the number of rotations in a time frame and converts the rotation measurement into a wind speed metric. However, unlike vane anemometers, cup anemometers do not need to be facing the wind force to take a wind speed measurement.

Cup Anemometer Applications:

Cup anemometers generally have a broad measurement range making them well suited to outdoor environments. Applications for cup anemometers include measuring wind speed at:

• Construction sites
• Mines
• Building sites, particularly when cranes are used
• Farms; and
• Schools.

Product Example: WR-3 Plus Wireless Anemometer Kit Product code: WR3PKit The WR3PKit comprises a waterproof anemometer and a robust handheld display with a 500-metre wireless range. This cup anemometer kit accurately measures wind speed, temperature, and air pressure.   Wind measurement range: 0.3 to 50 m/s Accuracy: 2% FS

Figure 3 Hot wire anemometer

3. What Is a Hotwire Anemometer?

Hotwire anemometers work using the principle that the cooling effect of wind flow extracts heat. They comprise a fine, electrically heated wire on the sensor that’s heated slightly above ambient temperature. The device will keep the wire at a constant temperature whenever any airflow starts to cool it. The meter will then measure the amount of current needed to keep the wire’s temperature constant and convert this to an air velocity reading.

Hot Wire Anemometer Applications:

Hotwire anemometers perform best in environments with relatively stable and constant temperatures, for example:

• Checking flow foods
• Exhaust monitoring; and
• Various other HVAC applications.

Product example: Testo 405i Smart Hot Wire Anemometer Product code: IC-0560-1405 The Testo 405i is a Bluetooth enabled anemometer that takes accurate air velocity, temperature, indoor air velocity and volume flow measurements and sends results to your smartphone via Bluetooth. With the extendable telescopic shaft up to 400mm, the IC-0560-1405 is ideal for measuring tasks in ventilation ducts.   Wind measurement range: 0 to 30 m/s Accuracy: ±(0.1 m/s + 5 % of m.v.) (0 to 2 m/s) ±(0.3 m/s + 5 % of m.v.) (2 to 15 m/s)

Figure 4 Ultrasonic anemometer sensor

4. What Is an Ultrasonic Anemometer?

Ultrasonic anemometers use sonic pulses to precisely measure wind speed. Sonic pulses are created and sent via sensors on either side of an opening on the anemometer. As wind speed increases, the sonic pulses ability to cross the junction is compromised. The anemometer uses this information to calculate wind speed.

Ultrasonic Anemometer Applications:

An ultrasonic anemometer generally has no moving parts and requires very little maintenance, making them item wind measuring devices for long term and remote deployments, including;

• Mine sites
• Construction sites
• Tower cranes
• Weather buoys; and
• In environments with salty air or large amounts of dust could affect the accuracy and reliability of traditional cup or vane anemometers.

Product example: Sonic Anemometer Product code: IC-6415 The IC-6415 Sonic Anemometer by Davis Instruments provides instantaneous and effortless wind speed and direction measurements using ultrasonic waves. The unit measures wind speed and direction using no moving parts, ensuring minimal maintenance. Get our scientists' review of the IC-6415 here.   Wind measurement range: 0 to 89 mph, 0 to 78 knots, 0 to 40 m/s, 0 to 144 km/h Accuracy: ±2 mph (2 kts, 3 km/h, 1 m/s) or ±4% whichever is greater

Figure 5 Pitot Tube

5. What Is a Pitot Tube Anemometer?

Pitot Tube Anemometers are suitable for measuring mid-range to high-velocity and temperature airflow. A pitot tube design generally has two holes. The first hole at the front faces the wind direction and measures stagnation pressure (i.e., the static pressure at a stagnation point in a fluid flow). The second hole is located on the side of the pitot tube and measures static pressure (i.e., the resistance to airflow in ductwork or other components). These devices calculate the difference between these two pressure measurements to generate a dynamic pressure reading and convert that reading to a wind velocity measurement.

Pitot Tube Anemometer Applications:

Pitot tube anemometers are suitable for use in high temperature and high wind velocity environments, for example, monitoring:

• HVAC/R systems
• Exhaust vents; and
• Flow hoods

Product example: Pitot Tube Anemometer with Differential Manometer Product code: HD350 The handheld HD350 Pitot Tube Anemometer is a multifunction tool that measures airflow, air velocity, pressure and temperature. The unit comes with a pitot tube, Windows compatible software, a hard carrying case, a 9V battery and two 85cm connection hoses.   Wind measurement range: 0 to 89 mph, 0 to 78 knots, 0 to 40 m/s, 0 to 144 km/h Accuracy: ±2 mph (2 kts, 3 km/h, 1 m/s) or ±4% whichever is greater

Conclusion: What is an Anemometer?

Unlike the pronunciation of these instruments, the answer to the question “What is an Anemometer?” is straightforward. Anemometers are super useful, easy-to-use devices used to measure wind speed for a host of industry, community, educational, and agricultural applications.

View all anemometers here

Need advice or assistance finding the best anemometer for your application? Speak with an Instrument Choice Scientist: Call 1300 737 871 or email [email protected].