Roommate issue

Hi everyone I’m coming to you guys as my last straw. Basically we have three people who live in this apartment and 1 including myself. Recently in may I had a girl move in here and and she likes to have the AC on all night at around 73°. In our apartment that shit is COLDDDD. She also doesn’t have a window in her room but she knew that before moving in. I addressed the issue to her the first time around and she basically said she “needs” to have it on. I couldn’t 1 vs 1 her because my other housemate was moving out so I waited until my new housemate moved in. I had the AC conversation with her last month again because the bill came out to $250 FOR AN APARTMENT and I genuinely felt cold. Mind you this is what my dad pays with a family of 5 in a TWO STORY HOME in the summer. This is an apartment. She basically said she can put it up 2 degrees higher… like she has to be rage baiting me right? Idc if the AC is on like that during the day WHEN ITS ACTUALLY HOT but for someone living right next to the beach it gets cold here at night. Fast forward the bill comes out for this month and it’s $250 again and this time my new housemate jumps in and basically feels the same way about the situation of how it’s too cold and it’s too much to pay for that especially as college students. The other roommate is still persistent on keeping the AC on at night because she “needs” it. At this point idk what to do I feel like we’ve been so nice to her and tried coming to a conclusion to keep the AC at a higher temperature but she doesn’t budge. She offered to pay more to keep it on but that doesn’t really help because we’re still so cold at night and mind you we live in SoCal and the fact that we get cold at night just shows how low the temperature is in our apartment.

Any advice on how to handle this situation because we tried being nice for three month actually and nothing is working.