Wiindow air conditioner query, including amps, 220v

I need to replace a 20-year-old through-the-wall air conditioner in my condo living room. (It was here when I bought the place 5 years ago). I'm basically gonna get all the BTUs I can stuff into my 26-inch wide sleeve. But I have a couple of questions.
--Is there any disadvantage to getting a 220 volt unit? I tested an unused 220V outlet near the AC and found it working. (As a bonus, I solved the mystery of what one of that unlabelled circuit breakers in my box is for.) The big attraction is that the AC would be on its own circuit with a 20 amp breaker.
--If I go with a 110v, how many amps can I safely go up to? The circuit's on a 20 amp breaker, but there's LOT of other stuff on the same circuit. The whole living room: TV, Tivo, stereo amp, 4 lights. I've never blown a breaker so far, but I don't have any easy of figuring out how many amps my current unit sucks up. So what should my margin of safety be?
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higgins wrote:

Get a 220V unless you find a big enough 110v unit on sale or something.
There's no need to plug the 110v unit in with everything else -- you convert the 220v circuit to 110v easily and have a dedicated 20A 110v circuit if you end up with a 110v AC. Just move the white or red wire from the breaker to the neutral bar in the breaker box, and replace the outlet with a 110v 20A outlet. Save the 220v outlet in case you need to change it back.
I cool my whole house with two 8000 BTU AC's with EER's > 10; one upstairs that probably does most of the work, and one downstairs that pretends to do all the work. The one upstairs is plugged in with DD's computer and everything else plugged in up there. That's one reason the high EER was important.
Best regards, Bob
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Not always a good idea. Too bit is worse that too small. Plenty of posts on that here.

Operating cost is the same. Laarge appliances and tools use 220 as they wraw less asmps making for smaller wires to run.
(As a bonus, I

That would be good.

This is ot good. When the AC compressor kicks in, it will cause a voltage drop and that is not good for all the electroncis. Maximum total load on that should be 16A.

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220V A/C's are marginally more efficient than 110V units of equivalent BTU.

Don't even bother. The largest 110V A/C's are in the range of 10K-12K BTUs, not worth their weight except for small areas, and these units will take a large chunk of that 20A -- at least 9 or 10A and possibly up to 14 or 15A. No reason to do that if you have a dedicated 220V circuit.
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Huge advantage. You can about double the btu size of the unit you buy.

After 20 years, do yourself a favor and run a new wire.
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A new wire from the outlet to the circuit box??? Or from the box to something more centrail?? (note that I live in a 4th floor condo).
As for BTUs, this unit would be in a 22 x 12 living room that is wide open to a 12 x 10 dining room and a large kitchen. I'm probably going to end up in the 12k-15k BTU range. I doubt that's too much in this setup. I doub tthat it's ENOUGH in this setup, but I'm constrained by the dimensions of the wall sleeve.
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