A savvy renter will prefer to rent a place with a nest thermostat installed, all other things equal.

RECORD COLD Temps below ZERO TIP: How to keep your pipes from freezingTurn on faucets allowing them to run a faster than a drip.. a very slow stream -, BOTH Hot and Cold,OPEN The Cabinet Doors BELOW All of your sinks, kitchen, bathrooms, etc.Turn up your thermostat now to get a head start before below zero temps arrive.Laundry Room - Washer, dryer - if your washer and dryer is against an outside wall, please unscrew you hot and cold water hoses from your washer and place them in your washer (the same place you place clothes) and let the hoses just dangle in there.

i think thermostats are huge.  

replace oil furnace with gas furnace with 3 zones/thermostats/loops/pumps - none of them 'slave' zones - that's what i'd do in philly

Setting up Wifi will also lets you setup smart thermostats and cameras.

Optimize HVAC for the SpaceMigrating one's STR's pellet stove + electric baseboard heating to a $5k 28k DIY mini-split + baseboard dropped my electric bill 50% in a New England STR, but that's with extensive automation of heating cycles, retrofitting of electric heaters w/smart thermostats, and understanding that splits / heat pumps do lose effectiveness in their ability to extract heat from very cold air.

He suggested tenants not to turn on the thermostat any more as it may cause fire and carbon monoxide etc. 

Again, anticipate immediate repairs being required.Lastly, while each of these systems is zoned and allows each tenant to have control of their own thermostat and heat setting, they are only connected to one gas meter.

Nest camera's overlooking the front door and Nest thermostats controlling the A/C.

Even if they do, just get a wifi connected thermostat and home control system and you are set.