Sounds like you have a good plan. Just be sure everything in the filter stays wet, and doesn't restrict water flow and you'll be fine.
If at all possible, you should just leave your other filter running along side this one. There is a bunch of bacteria living on the filter. You will be less likely to cause an interruption in your tanks cycle. However if your tank has matured for more than a year I would worry less about it.
Good choice on the AC. Money well spent.