[UNKNOWN] 3 is the first connective thermostat that works with Apple's Home Kit, so you can enable, disable, and adjust the thermostat using Siri, making it a great choice for iOS users.
Beyond that, the smart thermostat has a lot of the usual features you'd expect.
It has an accompanying app and a feature that automatically adjusts the temperature when it knows you're away.
Look out for the third generation version of the Nest learning thermostat.
The new model has a fresh design with a larger screen and slimmer profile.
Besides the usual smart learning features, the thermostat can integrate with the Nest security camera and Nest smoke detector Finally, Honeywell's [UNKNOWN] thermostat using geofencing to know when you're away.
You can set either a 500 foot or 7 mile range.
When you're out of range, it goes into away mode, and when you're back in, home mode will kick back in so that it's warm when you get home.
In San Fransisco, I'm Sharon Profis, CNET.
COM for CBS News.