On the bright side, the Lyric is outfitted with a humidity sensor that can trigger the ventilation system to move air around your home if the humidity gets too high (increasing the chances of mold growth).
Where the Nest depends on your walking past it to set off its proximity detector, the Lyric relies on the geo-fencing parameters you put into its smartphone app. Set a range — there are only two choices, 500 feet or 7 miles — and the app will create an invisible circle with a radius of that distance on its internal map. The instant you travel outside that circle, the thermostat will put your HVAC system into "away" mode to save energy. Come back inside that perimeter, and the thermostat will resume heating and cooling your home so that it's comfortable by the time you arrive (although the speed at which that happens is more a function of your HVAC system than the thermostat).
Geo-fencing sounds absolutely logical, and some high-end connected-home systems (Vivint and others) use the technology for similar purposes. It worked perfectly for me on the Lyric, lowering the temperature in this early winter (I live in the Midwest) each time I crossed my geo-fence, and boosting it back up so my home would be comfortable when I returned.
If multiple family members have smartphones, you can have each of them install the Lyric app and register their phones so that your HVAC system goes into "away" mode only after the last person leaves.
Nonetheless, there are limitations to what geo-fencing can do. If other family members who don't have smartphones (or visitors with smartphones that aren't registered to the thermostat) remain home when you leave, they might take it upon themselves to override the thermostat's programming to maintain a comfortable temperature while they're there — and they probably won't remember to reset it when they leave. Here's another scenario: If your smartphone battery dies while you're outside your geo-fence, the thermostat won't know when you cross back into your home zone (so keep a phone charger in your car).
Installing the Lyric
As I mentioned earlier, round thermostats are definitely old school. As such, installing one in place of the rectangular model I had before left me with some touch-up painting to do. I had the same issue with the Nest, but the Lyric's plastic construction looks relatively cheap compared to the Nest's steel and glass material.
You'll need to install three components: an optional wall plate that can hide old holes; a mounting plate that you wire your HVAC system to; and the thermostat itself, which snaps into the mounting plate. Honeywell provides an app for Android and iOS devices that steps you through the installation process. A printed instruction sheet would serve better, since you won't care if you drop it.
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