Bests & Worsts Reviews from Amazon

This is a good product with a quirk or two. There's a lot to like -- the display is large and readable, and there's plenty of wireless range. The remote unit will transmit from inside a closed refrigerator to the the indoor unit on a counter. That means if you put the remote unit inside a refrigerator or freezer you can monitor the temperature without opening the door (which would affect the temperature). Part of my job involves running a meteorological instrumentation network so I naturally put this through some tests. Temperature readings for the indoor and outdoor units agree within 0.2-0.9 degrees F across a wide range. That's very good for an inexpensive consumer-grade product. I haven't calibrated either unit against a precision thermometer. But in my experience most quality-control problems manifest in unit-to-unit variability rather than a systematic bias across units, so I doubt they are off my more than a degree or (at most) two. The only noteworthy problem I have found is that both the indoor and outdoor units take a long time to adjust to a change in temperature. For example I put them in the refrigerator, let them cool, then took them out, and kept track of the temperature. The time constant worked out to about 18 minutes for the indoor unit and 12 minutes for the outdoor unit (that is, it takes 18 or 12 minutes for the unit to adjust to 63% of the temperature change). In simpler terms, to fully reflect a substantial range in temperature will take on the order of half an hour. Granted this isn't the most sophisticated measurement protocol! For practical use this probably doesn't matter much since fast temperature changes aren't common. Also the adjustment will go faster if the remote unit is outdoors with wind blowing across it. Just be aware that if you move this unit to measure the temperature of a particular place (say, a hot attic or cold garage) it will take some time to adjust.