Extech 45158 Mini Thermo-Anemometer with Humidity


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Extech 45158 Mini Thermo-Anemometer with Humidity

Waterproof pocket size with Air Velocity, Temperature, Relative Humidity, Dew Point, and Windchill


The 45158 is a waterproof pocket sized Thermo-Anemometer for Air Velocity, Temperature and Wind-chill measurements. Simultaneously display Air Velocity and Temperature or Wind-chill on the LCD screen.


Selectable averaging function of 5, 10, or 13 second intervals. Fold up protective housing extends to 9 in. (229mm) for a better reach. Tripod mountable. Features Data Hold with Auto power off functions. Complete with battery and 43 in. lanyard.




  • Display Air Velocity and either Relative Humidity, Dew Point, Temperature or Windchill
  • Selectable averaging function of 5, 10, or 13 second intervals
  • Fold up protective housing extends to 9" (229mm) for better reach, Tripod mount
  • Data Hold with Auto power off
  • Water resistant housing floats


Waterproof Mini Thermo-Anemometer + Humidity

Model 45158 packs a lot of capability into a pocket size meter that displays air velocity plus temperature or air velocity plus relative humidity on a large, dual display LCD.

Features & Functions Overview

Wind speed values are displayed in six different units (feet/minute, meters/second, kilometers/hour, miles/hour, knots, and Beaufort) with +3% accuracy. Averaging for 2, 5, or 10-second intervals can be selected. Besides air velocity, it also measures wind chill plus relative humidity, and dew point. Additional Functions: Other features include Data Hold to freeze the most recent display, and Auto Power Off to preserve battery life. The 5-1/4" meter folds into a water-resistant housing that is designed to float and when the cover is open. The meter extends to 9" for reaching into openings. You’ll want to carry it with you whether you are on the job as an HVAC or plant maintenance technician or involved in recreational sports.

Anemometers measure moving air with a rotary sensor that acts very much like a weathervane and can be likened to the blades of a fan. The vane freely rotates in response to airflow, and as the air moves through the vane the blades turn in proportion to the speed of the air.

Cubic Feet per Minute (CFM) or Cubic Meters per Minute (CMM) are units of measure for air volume measurements. This is a measurement of the quantity of moving air through an air duct, passageway, or enclosure. In order to determine this, the area of the duct must be measured. The area value (in ft2 or m2) is entered by the user, by pushbutton or keypad into the meter and an air velocity is determined.


Click here for product datasheet


Measurements Range Resolution Basic Accuracy
ft/min (feet per minute) 100 to 5500 ft/min 20ft/min ± (3%rdg + 40ft/min)
m/s (meters per second) 0.5 to 28m/s 0.1m/s ± (3%rdg + 0.2m/s)
km/h (kilometers per hour 1.8 to 100.6 km/h 0.7km/h ± (3%rdg + 1.4km/h)
MPH (Miles per hour) 1.1 to 62.5 MPH 0.2MPH ± (3%rdg + 0.4MPH)
knots (nautical miles per hour) 1.0 to 54.3 knots 0.3knots ± (3%rdg + 0.6knots)
Beaufort Force 1 to 17 BF 1 BF ± 1
Temperature 0 to 122°F (-18 to 50°C) 0.1°F/°C ±1.8°F/±1°C
Relative Humidity (Model 45158) 10% to 95% 1% ± 4%
Dew Point (Model 45158) 32°F to 122°F ± 2%
Power CR2032 Lithium battery
Dimensions 5.25 x 2.75 x 0.75" (133 x 70 x 19mm)
Vane 1"(24mm) diameter
Weight 3oz (95g)
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  • Extech 45158 Mini Thermo-Anemometer with Humidity