Is OTHER wrong in the post ? POST : I live in a house with two other people.  The agreement was in exchange for exclusive use of the garage and driveway I would pay the electric.  

It worked out fine in summer and fall, but since it’s gotten cold the electric bill has gotten ridiculous.  Last month it was $162.  I’ve talked to the roommates about it and trying to cut the cost down.  They agreed, but roommate’s gf who is here almost every day is not following through.  She cranks the heat up and leaves it that way.  Even when she leaves. 

I talked to roommate about her doing this and he said he would talk to her again, yet today when I came home the house was empty and the heat was on 85.  I don’t want to cause drama with her so I’m thinking of installing a plastic cage over the thermostat that I would have the key to.  I wouldn’t let the house get freezing, but it would also prevent someone who doesn’t even live here from driving up the electric bill. 