My home is a bit larger square footage wise - AND I keep my garage AC'ed (not sure if he does or not). Just do a search - MAX this moron should be paying is maybe somewhere around $700... MAYBE. I don't give a fuck how hot it is. Who knows, maybe this dumbass porch banjo player leaves all of his windows and doors open.
Point is, if you are rocking a $1500+ electric bill in 4,300 square feet - you are doing it VERY wrong. You deserve what you get.
