Bests & Worsts Reviews from Amazon

Initially, I thought these were great. I purchased 4 sensors to go with my ecobee 3 thermostat. At first, everything worked very well. However, I've found that 2 of them lose connection with the thermostat quite frequently, even though none are far away. (I live in a condo, modern construction - no plaster with chicken wire or anything like that to interfere with signals). Worse than that, however, 3 of them have developed problems - either reporting activity levels that make no sense or becoming completely non-functional. I contacted the company, and they replaced one of them under warranty, but they ignored the problems with the other two, and stopped responding to my support requests regarding the other malfunctioning sensors (which were all reported at the same time). So unless you're comfortable with having to replace these after a couple years, you may want to reconsider. If they were priced at $15 each, I could live with a short life - but at these prices, I expect greater durability and reliability.