The Good: The $249 Ecobee3 comes with an installation workaround in case your system doesn't have a C wire, as well as a remote sensor that extends its temperature-and-motion-sensing range. The Bad: Many existing HVACs don't have or need a C wire, and Ecobee's fix isn't for novices. The Bottom Line: While the Ecobee3 doesn't quite match the design and usability of the Nest Learning Thermostat, it is definitely worthy of your consideration. Editors' note, June 10, 2016: This review has been updated with details on IFTTT, Amazon Alexa, and Apple HomeKit integrations. Editors' note, November 19, 2014: Ecobee recently released version 1.1.1 of its Ecobee3 app and adjusted the sensitivity of its touchscreen. I have since retested the thermostat and the text and overall score have been updated accordingly.Toronto-based Ecobee may not have the name recognition of \tHoneywell or Nest, but it was actually the first company to come out with an app-enabled thermostat. Its initial line of smart thermostats was funneled through dealers though, which limited the brand's ability to compete in the do-it-yourself arena.To satisfy this new market, the company has rolled out the $249 Ecobee3 (\u00a3155\/AU$285), a DIY climate kit comprised of a Wi-Fi thermostat and a remote temperature sensor that work with \tIFTTT, Amazon Alexa, Apple HomeKit and more. It doesn't quite have the same design appeal as Nest, but the Ecobee3 is a thermostat I can wholeheartedly recommend.Getting startedYour installation \tsuccess will vary a lot depending on your HVAC system and your level of electrical wiring savvy. The ideal will have a five-wire system, in which case you can literally just swap out your old thermostat for your new Ecobee3.If your HVAC unit only has four wires running to your thermostat, you're not out of luck, but you will have an extra step to deal with. The Ecobee3 requires a C (or Common) wire connection, which you won't find on a four-wire HVAC system. To get around this problem, Ecobee includes something called a Power Extender Kit with your purchase free of charge that does the work of the C wire without you actually having to add that pesky fifth wire yourself (or having to call an electrician to do it for you).You will need to know your way around your HVAC system to install the Extender Kit, since you need to connect it directly to the controller board on your HVAC unit, provided yours is new enough to have one. If not, you can still reconfigure the wiring, but budding DIYers will likely want to call in some experienced help. Whether you use the Extender Kit or not, this all seems unnecessary given that the competing \tHoneywell Lyric and Nest Learning Thermostat will both work fine on a four-wire system.For my own installation, I had to go with the rewire option given my near 20-year old HVAC unit. I had help from Steve Conaway, one of our technical editors, who rewired my unit to give it a C wire. It worked, but it certainly wasn't convenient.Once the Ecobee3 was installed, it recognized the wires I connected and walked me through the configuration process. This included adding my home Wi-Fi details, selecting Fahrenheit or Celsius -- all of the stuff you'd expect from an initial thermostat setup. I also paired the included remote sensor to the thermostat, which took about a minute. The remote sensor is a handy extra that comes with the Ecobee3. It essentially acts as a standalone ambient indoor temperature monitor you can put in another room. It can also tell the thermostat whether you're home or away.Registration is the final hurdle between connecting your thermostat to the Web and mobile apps and enjoying the full functionality of your Ecobee3. The early production versions of both were extremely glitchy, but I revisited them about 6 weeks after the original review date. The displays looks the same, but the wonky usability issues are gone. That means that you can expect a much breezier registration process and interaction with the apps overall.