I wouldn’t let this person push the issue. She knew what she was getting into. Maybe she needs a better portable. Where there is a will….
That she brought up her kids is a red flag. Now you are the dirty landlord that doesn’t even care about her kids… Almost any amount of heat doesn’t phase reasonably tough healthy kids…sounds like a personal problem. My kids live in east county and have never ever been the first ones to ask to put the air conditioner on.
There are options for cooling off and getting homework done that people all over the county choose for themselves, instead of putting it on the landlord. Don’t let her be an irresponsible problem child.