In the common areas and in the bathrooms, I installed Cadet Energy Plus in wall heaters, with digital thermostats. 

They were over an hour and a half late to checkout, left the thermostat at 80 degrees (the house is in Wisconsin so it's winter but 80 degrees???).

Another they turned off the thermostat and failed to turn it back on, resulting in frozen plumbing.

The HVAC person put in a split, so now there are 2 thermostats, one downstairs and one upstairs. 

I don’t need a lot of bandwidth: all I need to do is to control the locks, two thermostats and an outside camera.

Sure no heating or no cooling could be a much bigger issue, but if we're requiring and reminding tenants to be changing filters quarterly the chances of the heating issue being a quick reset on the motherboard or troubleshooting on the thermostat are high. 

I may stop by the property to change a filter, and every light in the house is on, the tenants take hour-long showers, and keep the thermostat wherever they please.

I use it to make sure the temp matches our thermostat.

One unit houses the thermostat for the furnace which heats the whole building.

Is it legal to put a lock box on the thermostat?