I did not buy this product new. The house I bought had one. 4 days after I reprogrammed the thermostat, it stopped working. Unfortunately, this was the coldest night of the year. At least I was able to use it as a smart device for a few days before it failed.
The thermistar was installed in our house when we bought it. After living in it for a year I finally took the time to figure out how to hook it up to our wifi. It is so handy to be able to control and monitor the thermistat remotely. I love it.