The Nest Thermostat is a smart device. It runs on a Linux-based platform. This thermostat has been designed to accept updates from the Nest cloud services, and it also automatically receives firmware updates. This device comes equipped with a USB port that is normally used for service but it also provides a quick way to charge the thermostat, to manually deliver software updates, for a service technician to use when troubleshooting the device and also as a way to restart the thermostat when all other steps have failed.
These thermostats use power running through HVAC wires to charge. If you find your thermostat with a red blinking light, this means the battery is low and will require recharging. For a much faster charge, the thermostat comes with a power cord with a USB port. This can be plugged into a wall charger or into the USB port on your computer to quickly charge up the thermostat battery. Circumstances that might precipitate the need to recharge the thermostat quickly could include a power outage. Having a portable USB charger, that has a portable battery pack, on-hand will allow Nest thermostat charging without the need for electricity at all. The USB cord also makes it possible to recharge the device from any automotive DC outlet with the use of a mini USB charger.
Another way the USB port can be used is, if after taking troubleshooting steps to turn the thermostat on prove unsuccessful, you can use the power cord to start it up. This is done by removing the thermostat from the base. The USB connector on the back of the display. Plug the USB cord into the connector and then attach it to a power source. The screen should light up and will ask you to attach it to the base. If this does not help, you should contact Nest support.
All in all, the Nest Smart Thermostat is an awesome device and there are multiple reasons that it was named the best smart thermostat 2017 by several sources.
Image Source: https://en.wikipedia.org/wiki/Nest_Labs