Also, trying to save money on thermostats, I ruined the boiler control board -- a $650 extra expense.

I am looking for a thermostat that I can install where I can set the upper and lower limits of the temperature - perhaps by a passcode. 

I currently have a 2 unit on oil heat, 1 thermostat, shared ducts, so I have to foot the entire bill and it's killing my revenue in the winter, costing $1000 some months.I've looked into converting to gas and into installing electric baseboard heaters.

I checked the thermostat.

She had already checked the circuit breaker, changed the filters and changed the battery in the thermostat.

I would assume there would be problems if only one tenant is controlling the thermostat.

.- Use smart thermostats that only allow tenants to have heat within a specified time- Has energy been deregulated in your area?

Electricity can top $500/600 per month during peak monthsTurning the thermostat up to 80 during the summer is still $350/monthNatural gas used only to heat showers is $50-80 a monthWater is at least $100 a month winter, $300 summer (sprinklers)Internet is $50 a monthI know "bills paid" is never a good idea, as tenants won't be efficient.But, "all bills paid" is the norm in this area for roommates.

I got a head start on a few things, and I bought a couple of 7 day programmable thermostats; they are Honeywell RTH2510B thermostats. 

Like dust the top of doors and the top of the thermostat.