A good option is to be living somewhere in the north and not south, and use a room in your house with multiple windows in it so you can basically just create a wind tunnel of cool fresh air. If that's not an option, then an AC is definitely for you, but don't overestimate how much these things need. I'm cooling my 20 miner farm with a 14,000 BTU AC and the temps are fine. Obviously they're going to put out more than that, you just have to exhaust their heat well.
How many cubic feet are you cooling with that 14,000 BTU A/C unit? Also what do you keep the temp of that area? I ask because that is *exactly* what I was going to use for my setup after researching
I figure cooling as small an area as possible with a 70F miner inlet temp along and proper waste heat removal will do the trick. It depends on your environment. If you use a room in your house you have excellent insulation rather than renting a warehouse unit or something. It means that if you can exhaust all of the hot air that the miners spit out so it's not recirculated into their intake using a window in the room, and you can introduce cool/room temp air to their intakes via the rest of the house/portable AC/another window, you'll be fine.
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