Extech SDL350 is no longer manufactured.

Instruments that measure air velocity and air/surface temperatures are one of the most important tools an HVAC tech will have in his tool box. With these meters seeing everyday use, it is imperative that you understand the limitations of certain instruments and select the correct one. Having the right tool will help grow your business and will pay for itself and then some. With so many options out there, I wanted to highlight a few models from Extech and discuss what sets them apart.

The first models I will be going over are the Extech AN100 and Extech AN200 Thermo-Anemometers. These would be considered entry level meters and as such, you will find fewer functions than other meters. The Extech AN100 will measure Air Velocity (80-5900 ft/min) and Temperature (14-140 F) while calculating Air Flow (0 – 9999 CFM). The Accuracy for this unit is within 3% of the reading for velocity and within 2 Degrees F for the temperature. The Extech AN200 is the same unit except it also adds an Infrared Thermometer in the top of the unit as well as calculating the Air Flow up to 999,999 CFM. Both of these units use a plug in 2.89” Rotating Vane to take its velocity measurements. These two units each come with a 1 year warranty.

The next model up is the Extech HD300 Thermo-Anemometer. This model is very similar to the previous model, AN200. It also has the built in IR Thermometer and calculates the Air Flow up to 999,999CFM. The big difference for this model compared to the others is the ability to datalog directly to a PC using the included software. The Extech HD300 Thermo-Anemometer also has a beefed up warranty that is 3 years.

Moving up from the HD300 is the Extech 407113 High Temperature Anemometer. As the name implies, this meter can handle a higher temperature, which is 32 to 175 Degrees F. Instead of the standard vane probe encased in plastic, this one features a Metal Vane to handle the higher temperatures. The Air Velocity is also different as it measures ft/min from 100-6890. The accuracy for the Extech 407113 is improved at +2%. Also, the unit also has optional software and datalogger if you needed those. This model also features a 3 year factory warranty.

Our last two models feature a hot wire and a mini rotating vane at the tip of the probe. The Extech 407123 HD Hot Wire Thermo-Anemometer has a telescoping probe that extends up to 7 ft. This makes it convenient from taking ceiling measurements without the need to move ladders all over the place. You can also get into small areas with ease. The Air Velocity range is not as large as the Rotating Vanes but still a respectable 40 to 3940 ft/min. The one downfall of this unit is that it does not calculate the Air Flow, or CFM. This unit also sports a 3 year factory warranty as well as the option to add software or datalogging capabilities.

The last model on the agenda is the Extech 407119 Hot Wire CFM Anemometer. This model also has a telescoping probe that extends up to 5.5ft. The Air Velocity is measured from 40-3346 ft/min. As the name implies, this model does calculate CFM from 0 – 999,999 CFM. Similar to the previous few models, the software and datalogging are both options you can add separately. The Extech 407119 also features a 3 year warranty and the accuries for Air Velocity is within 2% and the temperature is within 1.5 Degrees F.

Selecting the right unit is important, as wasting time with the wrong unit can cost you money. I hope this helped highlight some of the differences that you can find in different units.

Cheers and Happy Testing,

-Sam