What should I say to them?

How do you get your roommates to turn their a/c on if they don't like to use it? Its friggin hot in this apartment and I feel like Im in a hot box. I have two fans on and still feel like Im gonna sweat my skin off. What do I do? Do you think if I talk to them that they might just keep it on until night time and then turn it off? Im like really pregnant and Im twice as hot as normal people lol so do you think they will understand? I already pay half of everything so the elec. bill being a bit over wont bother me at all. I want to be comfortable and I know they do to I just need an easy way of telling them to turn the damn thing on lol thank you for your input.