🌡️ Mengshen M86 Digital Temperature and Humidity Meter with Dew Point and Wet Bulb Temperature - Battery Included: A Comprehensive Measurement Device Review

I received this instrument yesterday and it shows deviations of +5° to +6° when delivered. No way to calibrate either. I wouldn't buy any. I have 40 years in HVAC and I was hoping this would work. I'm sorry I bought

I bought this to better control underground humidity. When I'm done, I'll probably use it twice a year. That being said, I really appreciate that 1) it runs on 9V and 2) there are NO SCREWS to disconnect the battery. I have many great meters for various things, very good quality but ruined by having to dig up a screwdriver to install/remove leaking AA or AAA.

Very satisfied. The readings matched well with local predictions when I tested outdoors. Now you can be sure what the relative humidity is in my house. A few criticisms: Some fonts on the display are too small, response times are a bit slow for big changes (e.g. moving to a colder room), changing modes requires pressing the mode button longer than expected.

I'm an HVAC technician and it seems like good quality for the price, seems sturdy, don't want it hanging around in a tool box but on a bracket it seems to hold up. A backlight would have helped but seems accurate. Used only once to check wet bulb return temperature. Revain has another one of these brands, it's $35 and the only difference I've found is the backlight. If you don't need a light, I think this $25 will do just fine.

Just received. I bought it to measure wet bulb temperature for use in HVAC applications. This instrument measures temperature and humidity, and then calculates the wet-bulb temperature using a complex (built-in) algorithm. I didn't want to carry around a computer with a wet-bulb temperature chart. I have not compared this device's measurements to any other standard, but I have no reason to believe it is not accurate. Seems good value for what I paid. Delivery was promised 2 days.

I wonder if there are fakes out there. It's not like the photo. There is no name on my device, box and instructions (except for a small label accidentally pasted on the back of the box), no country of origin, no warranty information. It does not meet the specified specifications. It also shows what I call "Judder". Leave it in a stable spot for an hour, turn it on and the temperature will rise a few degrees Fahrenheit for a few minutes and then jump into the 2 degree range without stabilizing…

*Updated 12/20/17*: Upon further inspection (I re-read the manual to find calibration information I may have missed) I noticed a passage that says, that accuracy cannot be achieved outside 64F-82F (18C-28C) or below 20%/above 80% humidity. So under a variety of normal conditions (at least where I live) it cannot be relied upon. The website says 20°C to 80°C (-4°F - 176°F), which is *very* different, although it shows an error of +/-3% RH. It all boils down to this device being suitable for my…