The Good: Ecobee's $249 Ecobee4 Smart Thermostat has a responsive display, a remote sensor and tons of smart integrations, including a built-in Amazon Alexa speaker. The Bad: The price is high, particularly if you don't care about the Alexa speaker or the Ecobee4's other smart capabilities. The Bottom Line: There's no comparison -- the Ecobee4 is the best smart thermostat available today. Editors' note (Nov. 14, 2017): The Ecobee4 now works with the Google Assistant and supports Amazon's ESP feature. \tEditors' note (May 9, 2017): Amazon introduced Echo-to-Echo Alexa voice calling today. This feature isn't currently supported by the Ecobee4 thermostat. \tThe $249 Ecobee4 borrows all of the best stuff from Ecobee's older thermostats. It has a responsive touchscreen display, a remote temperature and proximity sensor, intuitive mobile and web apps and integrations with Amazon Alexa, Apple HomeKit, Samsung SmartThings and IFTTT. But instead of simply working with Alexa, the Ecobee4 itself is an Amazon speaker. (The Ecobee4 is only available in the US; at the current exchange rate, pricing converts to roughly \u00a3190\/AU$330.) \tNot only does the Ecobee4 work incredibly well, it's the smartest thermostat we've ever reviewed. For these reasons, we've given it a CNET Editors' Choice Award. If you don't want all of these smarts (or if you already have an Alexa speaker), consider one of Ecobee's less expensive thermostats or Honeywell's $150 Lyric T5. Otherwise, I'd strongly suggest the Ecobee4. \t \t \t \t \t \t \tWhat's all the buzz about? Ecobee's been in the thermostat biz for a long time, but its first few smart models weren't quite able match the appeal of Nest's stylish Learning Thermostat. Flash forward six years and Nest still sells the same ol' thermostat for the same $249 price. During this time, Ecobee has forged ahead with a lineup of three connected thermostats: the $169Ecobee3 Lite, the $199 Ecobee3 -- and the new Ecobee4. The Ecobee4's design still can't match Nest's gorgeous iPod-inspired thermostat, but it dominates in every other category. Its touchscreen display is easy to use and fast to respond. Instead of Nest's predictive algorithm, the Ecobee4 relies on a remote sensor. Complete with temperature and motion\/proximity detection, the sensor makes it easier to determine if someone's home or away. It's also a nice accessory for tracking rooms with hot or cold spots. I installed the sensor for our review unit at the CNET Smart Home in a basement bourbon storage room to monitor temperature. \tA Power Extender Kit (PEK) comes with your Ecobee4 purchase, too. Since this thermostat requires a C-wire to operate, you can use the PEK to add in the extra wire's functionality without rewiring your entire HVAC system. Want to know more about C-wires? Check out this article. Always consult a professional installer if you have questions about your thermostat's configuration. But if you're familiar with electrical wiring and you don't need to use the PEK, the installation should take less than 30 minutes.