You don't have to run it all the time, or even full blast. It just needs to be available. And when the heat wave comes, just use it to him one room, and just a little.

Cooling is expensive. My in-laws run their AC at full blast all day, it's like 65f in their house, it's cold. And then they complainb about cooling costs 🙄

In my last apartment, it came with a big unit in the wall in the living room. We almost never used it. We kept the windows open and let it be hot. We were hardly home during the day anyway.

Instead, we put a tiny unit in the window of our small bedroom. Then we'd only run it at night, and even then we'd keep it set to a pretty warm temperature. The goal was just to cut the humidity and make it slightly cooler than "uncomfortably warm", so we could sleep without sweating.