Flatmate issues

Hi! I moved in the flat I am currently living in September and although I get along with all of my flatmates, more or less, I was considering leaving because of some problems I could not stand - such as dirt, extra consumption of gas, arrogance...

One of my flatmate - the one I get on with the most - asked me to move in with her from next academic year and I agreed based on the fact that we get on really well with one another. However, we had quite a fight when I told her to turn the heatings off and she refused because she wanted to walk through the house only in a T-shirt. I might have exaggerated but I don't want to pay more for bills than rent so I got mad at her.

Today I was considering the pros and the cons to move in with her but I really don't know what to do.

PROS: she's clean, she respects me, she's fun, she's more experience than me (she's third year student)
CONS: she can be quite arrogant, she corrects everything I do, she likes leaving the heatings on for quite a lot, she has a bit of anger issues, if it's not her I wouldn't know with who else I could move.

What do you suggest?