How to ask a renter to use less power?

[Tyler Farstad]

I have a fully furnished condo where everything is included and a typical electricity bill for the month is $40 for the winter.  The tenant I have in there has it up to $140 this month.  I have let her know the power is way over normal at the beginning of December and silly me she seemed responsive and said she would try and keep it down.  

Does anyone have a good suggestion of what to say?   

I don't believe there is any recourse as we didn't build it into the lease.  Lesson learned.

Thanks for any and all suggestions.