Hello,
I live with a friend who owns the home we live in. We've had a silent argument for several years. We live in Texas so the summers are really hot! We have a many plants and have moved most of them to the kitchen table, where I put up heat reflective film on the windows in there, but she stated I was not allowed to do that in the living room. Well, it doesn't seem to sink in that if you leave the blinds and curtains open all day when no one is home that it costs more to cool the house down when you get home and the A/C bill is twice as expensive as it normally is. She leaves before I do in the morning, so normally I close them or at least close the curtains (which are very thin to begin with) to filter some of the heat source. But I come across a note in the bathroom today to leave the damn windows open so the plants that do not fit in the kitchen windows can get some light.
Can anyone think of any ways to explain this to her? We've even had a home energy audit that I scheduled and basically the guy said that is the main cause (us not able to change anything out financially) of our energy problems. She has never had to worry about money and we are both 31 years old. Her parents pay off all her credit cards and other bills, so she does not know what it's like to struggle and live paycheck to paycheck.

I am to the point where I know I will not be able to afford to stay here due to the electricity bill this summer, so my next step is to move out, which I really do not want to do. Any helpful advice is welcome!

Sounds like you will be moving. Unless you can get her parents to bail out your part of the bill tool. Until reality (bills) hits your roommate, you are going to fighting a losing battle with a short stick.

Is it the curtains being open that drives the bill up or is it the: loads of laundry,washer, dryer,long showers,lights left on, dish washer, hair dryer,hair straightener,coffee pot,2 or 3 tvs on, and so on they all add up. But yes the sades being closed will help in the heat of the day but I don't think it will solve the problem.

Actually it really is the blinds/curtains. I've finally gotten her into the habit of turning off powerstrips while we are gone all day, don't take long showers, we combine laundry and hang dry everything.
It's mainly the argument that the house is old with horrible insulation in the attic, single paned windows, and it just doesn't sink in that a window w/ no shade/trees around it heats up the house just as much.

This morning I decided to give up on the battle. I've already told her I have a budget for the summer and when I'm not able to pay for the bills all at once I'll just spread them out. Never signed a lease so nothing she can really do, and the bills are in her name only so won't ruin my credit. It's a losing battle.