Marmonix MAL900 Hot-Wire HVAC Anemometer with USB Logging

The Marmonix MAL900 hot wire anemometer measures air velocity, duct airflow and air temperature through a slim probe that fits small test holes and extends to 1000 mm. It reads 0.0–30.0 m/s from a 0.3 m/s start value at ±3% ±0.1, works out CFM or CMM once you key in the duct area, and shows air temperature from 0 to 45 °C at ±1.0 °C. Max, min and average values, data hold, 350 stored records and USB transfer to the PC software support balancing reports, and four AAA cells give about 20 hours of use. Browse all Marmonix anemometers, or compare the MAL-800 telescopic vane anemometer when a vane head suits the job better.

Marmonix MAL900 Anemometer

The Marmonix MAL900 Hot Wire Digital Anemometer is a precise instrument designed for measurement of wind velocity, airflow, and temperature. Its slim, extendable probe makes it ideal for confined spaces such as HVAC ducts. With functions like unit conversion, Max/Min and average flow calculation, 350-record storage, and USB connectivity, it provides professional accuracy for HVAC, industrial, and environmental applications.

The lightweight handheld design includes a large backlit LCD, audible key alerts, low-battery indication, and provides up to 20 hours of continuous operation on four AAA batteries, ensuring reliability in both field and laboratory conditions.

Marmonix MAL900 Key Features

Main MAL900 functions at a glance:

• High-accuracy hot-wire airflow and temperature measurement

• Multi-unit display: m/s, km/h, ft/min, knots, mph, CFM, CMM, °C/°F

• 350-record memory with USB PC data transfer

• Data hold, Min/Max, and average functions

• Large backlit LCD with audible key alert

• Slim probe, extendable up to 1000 mm for ducts and narrow spaces

• Auto power-off on battery, continuous on USB

• Low battery indication for reliable operation

• Lightweight handheld design, only 330 g net weight

Marmonix MAL900 Specifications

Power, size and weight of the MAL900:

• Power supply : AAA 1.5V Alkaline battery *4
• Low battery indicating :4V±0.2V
• Stand by current 0uA
• Operating Current ≤60mA
• Battery use life :20H (Continuous Use )
• Dimensions:
  • Meter :77x36x164mm
  • Probe 30.5×30.5x305MM
  • 30.5×30.5x1000MM(Elongated)
• Net Weight : 330G (Not Included Battery )

How hot-wire anemometers are used for duct airflow checks

When an HVAC contractor commissions or rebalances a building, each branch duct has to deliver its design airflow, and the figure is rarely measured directly. Instead, velocity is sampled across the duct and multiplied by the free area, the same flow = velocity × area relation printed in the MAL900 manual.

Air moves faster in the middle of a duct than near its walls, so a single reading can mislead. Testing, adjusting and balancing practice, such as ASHRAE Standard 111, uses a traverse: readings at a grid of points across the section, then an average. A thin hot-wire probe is suited to this because it slips through small drilled test holes and responds at low air speeds.

The technician enters the duct area once, steps the probe through the traverse points, and lets the meter average them into CFM or CMM. Stored results are later downloaded over USB for the balancing report.

Questions about the MAL900 hot-wire anemometer

How does the MAL900 calculate airflow?

Enter the duct area with the AREA key (m² for CMM, ft² for CFM) and hold the probe in the airstream; the meter multiplies velocity by area. A multi-point mode averages several readings across the duct, and a 2/3 Vmax mode estimates flow from the maximum velocity.

What ranges does the MAL900 cover?

Air velocity runs 0.0–30.0 m/s (0–5860 ft/min, 0–90 km/h, 0–65 mph, 0–55 knots), airflow 0–999,900 CFM or CMM with a 0.001–9999 area setting, and air temperature 0–45 °C (32–113 °F).

Can I move MAL900 readings to a computer?

Yes. Up to 350 records are kept in memory and transferred over USB to the supplied PC software. Auto power-off is bypassed while the meter runs on USB power, so long sessions are not cut short.