Roommate is turning up the heat in our suite and driving us insane

Basically our roommate, who is also our room advisor, has recently been turning our heat up to at least 90 degrees. It’s so horribly stuffy and suffocating and I hate waking up I. The middle of the night sweating to death. Even tour groups and the people who come over to visit comment on the heat. Everytime we turn it down she complains and turns it right back up again. It’s like she doesn’t care about how we feel. What should we do?