Extech RHM15 Mini Temp Indicator Review

Works as advertised! I've had it for a month now and have no problems. Accurate enough for my purposes. I mainly use it indoors to check the relative humidity on different floors in my 3 story townhouse.

I've had this meter for three months now with no problems. I still have to change the battery. The temperature shows the same as my digital thermometer wall clock. Humidity changes throughout the day, so I know it's an air reading, but I don't have anything to compare the readings to, so I'm just assuming it's fairly accurate.

Just what I needed to measure the humidity in the house and adjust my humidifier to keep my house comfortable and my guitars not damaged. During the Colorado winter, there can be incredibly dry indoor air that can cause stringed instruments to crackle. And it can be difficult to achieve adequate humidity levels throughout the home. This device is exactly what I needed.

I bought this Extech RHM15 and an Extech 445703 Hydrothermometer (larger) at the same time. Both have the same temperature, but this one has about 6-7 points humidity (about 20% difference). I was planning on using the larger unit in the room and the smaller one in the guitar case, but I'm not sure I trust that.

Poor calibration. Ordered from Revain and was intermittently in the lower part of the calibration range (reading 70% in a controlled environment of 75% RH), the rest of the time outside of the range (reading < 70% RH) . Revain replaced it without question, but the new device was even further out of range. These small units are NOT configured so you can adjust the relative humidity displayed like some other units. If you need to know what relative humidity is with any degree of accuracy…

I bought this device for two reasons. Firstly this Extech company has been around since 1971 and my other choice was Inkbird which has less than 10 guitars and secondly Taylor guitars list them on the website even though I don't have a Taylor. Also, the Inkbird and Oasis specs list a 30% RH lower limit, in their reviews people say they don't read at this point, while the Extech RMF15 shows up to 10%, which is more useful to me. It worked after I took out the battery which is the only way to…