TekpowerTP6252A Digital Anemometer Wind Speed Air Velocity Meter, Air Flow Meter, MS6252A,HYELEC 6252A

I was having issues balancing the airflow of our hot air heating system. This started my search for a reasonably priced tool to measure airflow at the output registers and the returns. This meter was reasonably priced and had good ratings/reviews so I purchased it. I was able to take readings at all of the heat output registers. This gave me real numbers to compare from register to register instead of just my feel that one had better airflow than the other(s). I was able to use this information to adjust the duct dampers and register vents to even out the airflow in the system. Overall we had better balanced heat in the house after the adjustments. This was way more cost effective then calling in a heating contractor to do this for us. Not sure when i'll need it again but I consider it a nice addition to my tools and worth the price even if I don't need it again.

Good performance and accuracies for an affordable price and convenient size, but requires setting to mph ("mil/h") or knots with each turn-on.

I bought the product earlier this year specifically to measure and verify CFM at the heat register of my HVAC installation that just completed recently. This thing is way off. It shows thousands of cubic feet per minute of air flow from a floor heat register. Not sure what this product is good for but it is totally useless at measuring CFM. I recommend not buying it.

Very nifty device to add to my ever-growing cadre of tools!I got this device to figure out if I was "choking off" one of my return air vents in my home's HVAC system. It looks like the HVAC was updated since the house was built in the 70's, because there are 2 chained air supply vents that feed the HVAC. One of them is right next to the blower motor and insanely loud. I dreamed up all sorts of plans to restrict/insulate/close off that air vent, but I didn't want to starve my HVAC system.So, I got this device in order to make sure the total CFM (Cubic Feet-per-Minute) of airflow into my HVAC was staying about the same as I messed with things.When selecting the "CFM" setting of this device, it asks you for the size of the opening you're measuring. For me, it was a rectangular opening, so that's easy to figure out (width x height). I then places this device sitting on the bottom ledge of the opening, and then turned on my HVAC. I did this for both supply vents to figure out the total CFM of my HVAC system. Then, by placing this device in the non-messed-with vent, I could start insulating/blocking the problematic vent and make sure that the CFM handled by the other vent was drawing more air to make up for me plugging the other vent.Overall, this is a quality-feeling product that's pretty easy to use. Highly recommended.

Good for really light duty work. We tried to use it at our repair shop to test air compressor CFM. The fan blade blew apart after testing for about 1 minute. Use this only for light flow and you will probably be OK. I guess you get what you pay for.