We almost bought a portable AC at Lowe's/HD this week. In fact, they were on sale by Thursday.
Last Sunday, our main 15k AC froze up and wouldn't pump out cool air, only warm. The Mobile Tech couldn't get to us until late Monday. To sleep at night and when I couldn't stand it anymore in the afternoon, we closed the upstairs door and just ran 13.5k AC in bedroom.
When tech arrived, the inside temp was 91 deg in the LR with the AC off. But he couldn't find anything wrong. He did tell us to remove the filters and run the fan on High instead of AUTO. Since then, it's been working okay. Am looking at the temps in full sun in St Louis, 100 deg outside and is a balmy 80 deg inside. Fans definitely help move the air.