I am looking to add a remote thermostat system for an office building similar to Nest.

What about one furnace (with 3 zones and 3 thermostats)?

The smart thermostats are really cool, and you can also get the ones with body heat sensors or decibel meters if you’re worried about noise, but so far we’ve actually gone with the Mr Cool DIY split AC systems with the WiFi integration, and been very happy with them.

Hello BP community,I recently purchased a property that is heated by direct vented space heaters which is somewhat common in the area.The property was initially insured by Geico/Travlers however, I've just recieved a notice that they can no longer insure the property to due the lack of central heating and a thermostat control.

The thermostats were set at 68 with it over 80 in the house. 

I think the tenants just may not know how to operate the system or thermostat or something...

tl;dr: The thermostat broke, I fixed it. 

Guests often look for those.Have also seen a recent study that says that 82% of guest prefer to stay in smart home enabled properties and that 60% are willing to pay more to stay at those so I'd recommend adding smart home devices (locks, thermostats, Roku TVs) and clearly market those in your listings.

Should I install additional thermostat on the renting unit and better separate the meters.

I didn't replace the thermostat, because it was only about a year old at the time... and it failed last week, requiring a Saturday-night trip to replace it.The bathroom had been redone in the past couple of years, so I mostly left it alone.