In my newer vacation house i use a Honeywell Lyric after a debacle with 2 nests, the lyric is fantastic in remote operation and the app is easy to use. In my older primary residence I was unable to use the lyric due to not being able to string a c-wire easily for power, so instead i purchased a 2gig ct100 which works great with zwave and doesn't require a c-wire, runs off internal batteries, and they have not gone dead in over 9 months.

If you use a z-wave compatible thermo similar to my inexpensive 2gig ct100, you can also set up remote sensors and/or run zwave scenes (depending on the zwave hub) to customize your temp settings to the nth degree.

First alert makes a battery operated combo alert for both smoke & CO2, it is zwave only, so you need a zwave hub, been using them in 2 houses for over 6 months , no issues. Last time I checked, no one makes a hard wired model yet.

Funny, Just got a small cold spell here and my furnace turned on for the first time in months, checked the temp on my 2gig ct100 thermo and it actually has settings in half degree increments, never noticed it before..fyi