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AC's use electrical energy to take some heat energy, and move it outside. You can kinda reverse the process in certain types of heat pumps to generate power, but it's not even close to worth it, the efficiency is horrible.
You need a temperature gradient to capture heat energy, basically a cold thing and a hot thing, you harvest the energy as it moves from hot to cold. You've cooled your house down, and want to use the waste heat to create power, you'll either have to find a very cold place somewhere nearby (unlikely to be cold outside if you're using AC) or you can use the fact that your house is cold. So now you've both lost energy and heated up your house, because that lost energy has been added to the heat you originally tried to remove.
The simplified but always true rule of thumb is that whenever you use energy to create something from which you can harvest energy, you'll never be able to harvest more than what you spent. In reality you'll pretty much always lose energy trying to do this, I'm not aware of anything that's 100% efficient in both directions (or even one honestly).