Although Nest is often touted as the most sophisticated smart-thermostat company, it is facing increased competition from other thermostat makers such as ecobee and Alarm.com that are bolstering their capabilities. Apple also recently stopped selling the Nest thermostat as it looks to attract customers to its own HomeKit platform.

But the market is still growing rapidly. By the end of this year, smart thermostats will make up the majority of all thermostat sales in the U.S., according to Parks Associates.

The latest Nest thermostat has the same integration with Nest’s smoke alarm and camera as did previous iterations. Features include shutting off heating systems if the Protect senses carbon monoxide in the house and turning the Nest Cam on when the thermostat is put into away mode. 

From the article "Nest Unveils Its Third-Generation Thermostat Amid Increasing Competition" by Katherine Tweed.