Just a bit temperamental. Some guys seem to have more luck than others installing it; from my experience I've found the signal range to be very poor, the setup to be frustrating at times, Honeywell's support team to be less than helpful, and response times can be sluggish. A couple of guys on here seem to have the installation cracked although I'm not sure that they don't have to go back from time to time to tweak installations to make them work. I've made the switch to Heat Genius, which I'm much happier with and have in my own home. It has 90% of the features of Evohome, plus a few extras Evohome doesn't have, and doesn't seem to suffer from any of the aforementioned niggles