What are the best programmable keyless locks for your STR properties ?

Most long-term tenants don't require assistance more than a few times a year, say for a running toilet or help to reset the thermostat.

Future plans to cosmetically renovate 2 of 3 units, enhance curb appeal, and add modern touches (keyless entry, smart thermostats, etc.).

I will buy the programmable combination lock put in place so you can change the combo as needed. 

We did have a unit turnover that we raised rent on the unit $900/month (tenants were below market and we did a fairly extensive tenant turnover including removing texture ceiling, new base boards, painting all interior, getting a new range, adding a programmable thermometer, and redoing the balcony railing (new powder coat)).  

I had to do this with a recent renter who had a proxy of their choice view my property and then complained of trivial issues (a door being a little too tight, loose thermostat cover, etc) upon taking possession. 

The second floor unit thermostat is not working and the tenant said they have not used the heating system for over five years." 

My hvac technician suggested he install a landlord thermostat to keep her from running our current unit into the ground. does anyone else use these?

Paint: $50.00Bathroom Mirrors: $400.00Furnace: $750.00Upgrade Electric Box: $900.00Washer/Dryer: $1,500.00Refrigerator: $800.00Dishwasher: $450.00Nest Thermostat: $125.00Vanity Half Bath: $400.00Water Heater: $1,750.00Ceiling Fans: $400.00 What was the outcome?

It is 2 story with the thermostat upstairs and a valve by the furnace where you can direct heat or air either up or down.