BTMETERBT-100 Handheld Anemometer, Digital Wind Speed CFM Meter Gauge Air Flow Velocity Tester for HVAC Shooting Drone, Wind Chill, 14℉-113℉ Wind Temperature

I picked up the BTMETER BT‑100 Handheld Anemometer recently for drone flights and my RV HVAC checks—and it's quickly become my go-to gadget.For anyone serious about wind data—drone pilots, HVAC DIYers, sailors, hobbyists—the BTMETER BT‑100 delivers pro-grade features in a compact package. Accurate, versatile, and user-friendly with an unbeatable price tag. It’s earned a permanent spot in my toolkit.

Great little guy with accurate information and easy to use.

I bought this to use while sailing, both for wind speed and barometer readings for weather forecasting. It does both those tasks well enough. However, it comes with about the poorest user's manual I've ever seen. The one feature that most interests me is the ability to record barometer trends, but the manual only mentions it without explaining how it works. Useless! In the specifications section, there is a table of altitude vs. pressure, but without any indication of the units that are used. (They are meters and millibars.) It would also be nice to have some idea how long a set of batteries will last. The manufacturer should spend a few bucks and get someone who has something more than a Sesame Street grasp of the English language to write the manual.Aside from the documentation issue, I like the product and would recommend it.UPDATE: I ran some checks on this unit and found the following:The battery indicator is misleading. Using the supplied batteries (carbon-zinc, not alkaline - throw them away!), the battery indicator showed zero bars (discharged) after about 10 hours, but the unit continued to run (it does NOT shut itself off automatically) for nearly three more days. During that period, I periodically copied the stored barometer settings into an Excel spreadsheet and plotted the results. Contrary to what is said in the manual, the unit records the barometric pressure HOURLY as long as it is turned on, not every two hours as the manual states. The most recent reading is stored in register one, and earlier readings are shifted up one place when the new data point is stored. So, assuming the unit was powered on for the period of testing, the data in register 16 would be 16 hours old, and the data in register 5 would be five hours old. When I replaced the batteries, the stored data did not disappear, nor did the barometric calibration change. There is no obvious way to clear old data. When the unit is off, no changes to the stored data are made. When the batteries reach a certain discharge level, the backlight will no longer illuminate, and the screen will display "Er2" instead of the usual data. That's your cue to change batteries.When attempting to calibrate the barometer, the settings are made in millibars, not inches of mercury. So, if you know your local barometric pressure, you have to convert it to millibars to get the reading right. (1mb = 0.03"Hg, and 1013mb = 29.92"Hg) If you plan to use the instrument at sea level, and you are somewhere higher than sea level when you do your calibration, you can adjust your local barometer setting downward by 1mb or 0.03"Hg for each 30 feet above sea level your are at the moment. For example, my local barometer setting is 29.92 and I am 150 feet above sea level. I therefore set my barometer to 1008 mb (1013 - 150/30, or 29.92 - 0.15"Hg.) get 29.77"Hg at my elevation. If I then go down to sea level, the pressure will rise to agree with the local barometric pressure. The altitude readout on the instrument is effectively useless because there is no easy way to determine sea level pressure ahead of time, so the altitude reading won't be corrected for sea level pressure.The issued cited above would be problematic for a professional-grade instrument, but, for the price of this unit, you can easily ignore the problems and you can still get useful info. Enjoy!

Seems to be fairly accurate I use it to ✓ tte wind for my drone

After installing the batteries (a small screwdriver was included as a thoughtful accessory) it took less time to begin using this device than it took you to read this sentence. Press the "on" button and it begins reading instantly.The buttons are intuitive. Press "max/min" once and you'll get the maximum wind speed. Press it again to get minimum wind speed. Press it again to go back to normal mode. Similarly, "Avg" gives you average speed over time.Really like that this comes with a protective case.The backlight is very bright - even in daylight it makes reading so much easier. It's also a must-have at night (for those like me who may use it in darkness for measuring potential windchill). Backlight turns off automatically after 15 seconds (presumably to save battery life).I tried to see if this has auto-off feature but after leaving it on for several minutes it doesn't turn off. This can be a good thing when measuring min/max/avg wind speed though.Booklet that comes with this device states ±5% accuracy, and it's rated to 65mph (plenty fast wind speed for almost all occasions). These are decent accuracy and speed ratings for this great price range.Because this is a "directional dependent" device, I recommend using a wind sock or similar method of knowing wind direction. Aligning this device with the wind direction gives best results.

I bought these because I always wanted one but I've been able to do some experiments to validate some things. For example, I can tell the difference in air speed of a 4" versus 6" duct and the air speed between a fiberglass and "allergy" air filter.I have no idea how scientifically precise it is but the results seem reasonable. The blades seem well balanced and respond to light air flow and seemingly minor changes in air speed.The only thing I wished is that the display backlight would stay on longer but really I have no complaints.BT recommended