The best smart thermostats of 2019

Smart thermostats do more than automate a fixed heating and cooling schedule. These app-enabled smart home devices make it possible to adjust your thermostat whether you're on the couch, at the grocery store or on vacation -- anywhere your smartphone is connected to a cellular or a Wi-Fi network. Many of these devices also work with Alexa, Google Assistant and Siri now too, giving you yet another way to adjust your thermostat settings without having to stand directly in front of it. Some smart thermostat systems also use smart features like a motion sensor to determine if you're home or away and automatically change the temperature -- both heating and cooling -- for you. Other systems rely on a geofencing radius -- once you get a certain distance from your home, they switch to away mode and then back to home mode when you return.