I already wrote couple articles on why programmable wifi thermostats are awesome, but if you already have one, you know how easy it can be controlled with your phone. If you’re an Android user, a little Tasker and AutoVoice action will let you control your thermostat with your phone as well.
Norman A explains on his Svbtle blog that he used Tasker and AutoVoice, a powerhouse pair, to push voice commands through Google Now to the Nest app to set or change his home thermostat anywhere, just by speaking to his phone. The nice thing about the Nest app is that it works anywhere, so you don’t have to be near the thermostat or on the same network to use it, and while the setup does require a few added scripts and Tasker profiles, it’s not difficult to set up.
He walks you through the whole thing at the link below (complete with gifs to show you how everything looks) and links to all of the components required to set everything up. Keep in mind though that this works best on devices that support Google Now and touchless controls, so he used a Moto X and his Nexus 7, although a Nexus 5 or any phone with the Google Now Launcher installed. Hit the link below to see how it all works.