We PMs find that a surprising number of people don't really understand how a thermostat works. 

Here's a few things I use: Schlage Encode lock, EcoBee thermostat, definitely a cleaner (found with an app called Properly), asked for a handyman reference from the cleaner - he is great, 3 night minimum stay.

I ran into the same issues that you did… self managing is great, but you need help in order to scale and grow your businessSo now I’ve got people offshore managing my properties at a very high quality for a fraction of the cost, something worth considering.Mine can set door codes, message (or call) guests, schedule cleaners, adjust the thermostat, monitor my cameras, & call a plumber just as easily as a local PM can, for 1% of the costThey handle everything themselves and rarely need to get me involved in anything, it is the perfect hands off low cost operationI wrote much more about leveraging offshore assistants in this post here.

With wifi locks, wifi thermostat, wifi cameras and your team, you can easily do it.  

They love the view of the lake from our screened back porch that has rocking chairs.They love the water and the water toys we provide.I love my Honeywell wifi color touchscreen thermostats. 9000 series.I live my wifi Rheem water heaterI love my digital watchdog hardwired security cameras.

I dont get many Airbnb bookings so that is less of a concern for me.I have a lockbox that has never failed, never needed batteries so I haven't been motivated to fix what isn't broke.I do have wifi thermostats and hot water heater as well as hard wired security cameras (no batteries to replace)

Two - install a basic HVAC system that can be controlled by a thermostat. 

We have ring doorbells/floodlights, august smart locks, noise aware for outside noise monitoring, and nest thermostats in all of our units.Also, if you can, speak to the neighbors and introduce yourself.

Today she informed me that her son in law changed the thermostat in my unit and claims the neighbor next door has control of her furnace(not possible).

Get some Chicago control thermostats and you are set.