Home > Consumer Reviews > Honeywell TM005X Wireless Indoor/Outdoor Thermo-Hygrometer

I was most interested in the humidity measurement. I conducted a calibration with a sling psychrometer. A sling psychrometer measures wet bulb/dry bulb temperature and is the least expensive (albeit a bit tedious to use) and most accurate way to determine relative humidity (RH).

I needed to know relative humidity for curiosity indoors and for a chamber in my basement used to dry cure sausage (I needed a 70%RH environment). The Honeywell unit was spot on with the sling psychrometer (and temp. was accurate as well).

The unit is new; I need to check it over time for accuracy. However, it's running very well so far and the price is right. I'll be buying more remote sensors [...] I found the remote sensor part no. is TS33C, can find them on Amazon with that search).

The majority of complaints say the humidity is "off." However, I didn't see a single valid calibration conducted.

Update 01-March-2009
I just took the main unit, the sensor and sling psychrometer. The conditions in my home at time of testing were 68F and 30% relative humidity.

Main unit read 68.4F/30% RH
The Sensor: 68.0F/30% RH
Sling Psychrometer: 68F/31% RH

The sling psychrometer consists of two sealed thermometers and will never need a calibration, it is an accurate standard. This Honeywell Unit is pretty darn good.

This thermometer/hygrometer has a large, easy to read display. I bought this primarily for the hygrometer and it's proven to be sensitive and accurate, both indoors and out. The product comes with a wireless outdoor (or other location) sensor that is easy to set up. You can add two additional sensors (not included). Although it's designed to sit on a table or shelf, it can also be hung on the wall. This might affect the hygrometer's sensitivity since the sensors are on the back. Haven't tried the wall mount.

Works well except for slight differences in temperature and humidity between base and remote unit. Remote sender is being used for reporting conditions in my greenhouse. It serves that purpose very well.

It is a real bargain also.

I have purchased this due to the high reviews. It however turned out to be a disappointment. First of, I did followed the instructions to put batteries in remote unit first, reset it, then put batteries in the main unit. Every time the main unit gets reset, it seems to start from 80F temperature & 20% in humidify, and very slowly adjust from there. After numerous resets, I was still unable to get the main unit to display same info shown in the remote unit, even when placing them side by side. The main unit seems to always be 4-8% off in humidity compared to the remote unit. As for temperature, the main unit also varies from the remote unit. It can differentiate from 2.6 F to as accurate as 0.1 F, compared to data shown in remote unit. The remote seems more accurate then the main unit. The main unit and the remote unit have buttons (requires paper clip to reach) to adjust the display from Fahrenheit to Celsius & vice versa. I however, was unable to get the remote to display in Fahrenheit. It was stuck displaying in Celsius.

Other than these negatives, the unit itself is pretty nice. It has a big display; the digital numbers are about 1 inch in height in the main unit. The remote unit also has a digital display, although it's much smaller than the main unit. I guess if you're looking for a unit to just display the temperature, this may not be a bad device. However, as a hygrometer, this definitely is not the unit to be using for accuracy. I will be returning this unit, since I am looking for a hygrometer...

I purchased this sytem to monitor the humidity in a basement from the main level. It works great and the base system allows several other remote stations to make keeping track of temperatures and humidity simple.