They take into account the temperature each day and the size of the house, estimate how much oil your tenant will use, and estimate how long it will take to use up that tank of oil. 

In my 4-unit the pipes froze on one unit (single-digit temperature during the nights during that time).

Sometimes a temperature is a mental thing.

When temperatures are below freezing outside, condensation collects on the windows and other areas.

We are scheduled for concrete pour tomorrow but I am not sure if I should cancel it for reason below:1) temperature is dropping soon if I delay and concrete might not set right.2) my wife is giving birth sometime next week which results in further delay and I just wanted to get this project done with.3) winter is coming and if I don’t finish the walkway, hard for tenant to shovel, ice forms and it’s dangerous.What do you think I should do, delay or move forward with the concrete pour?

The efficiency / age of the furnace, the insulation value of the home, the windows, the temperature the tenants sets the thermostat at...With all these factors, I would never include heating oil in the rent.

Most homes have at least a heat pump Temperatures are many times in the 40's or below during winter months . 

Water leaking can cause mold issues, which lead to expensive mold remediation and mold restoration.Due to the desert hot temperatures, Air condition is another common repair issues in Las Vegas.  

A good realtor would make a phone call to the listing agent to "feel the temperature" of the property. 

So if there was an issue with their temperature, on my closed days, guess who drive 45 minutes to adjust the heat?