Help me buy a new Air Conditioner!!1?

Man, you’re asking a lot here.

To compare “apples to apples”, look at the various “energy efficiency” stickers on the competing models you look at. They are required to calculate energy usage (and cost) according to a certain formula, so their ratings of “average cost” per year should at least be based on similar costs of energy, for example, and usage rates.

What you pay will be related to how efficient the machine is versus competing brands, AND what kind of power it requires.

You are correct that power requirements vary quite a bit. There are a lot of 110 V units that will plug into “any outlet”. There are also 110 V units that require dedicated circuits because they draw so much amperage (their power requirements) that you would have trouble running them with anything else on the same circuit. And there are 220 V units that require the same kind of power as an electric range. (Electricians can usually install these circuits for you for a pretty reasonable charge, if you need one.)

As for your requirements, you’d be best off googling normal cooling requirements for your area… and thinking about darkening / reflective blinds for south-facing windows, for example, to aid in lessening the AC load.

If you can afford to buy 220 volt AC, instead of a 110 Volt, you will save a lot of money in the long run. a 110 volt AC generally will work itself to death to produce the BTUs you are requiring. a 220 volt AC is much better. it runs on a lower speed and produces all the cool air you will probably need. it will also last longer. of the 220 volt ACs i have purchased in the past, the squirrel cage fan was the very best. remember the words “squirrel cage”, when you talk to a saleman. also, remember to protect your AC in cold weather with a protective cover on the outside. the same saying goes for a window AC unit as with your automobile….“you take care of it and it will take care of you”.

You need to understand a little Physics here. Sorry.

First, when something is rated 12000 BTU that means 12000 BTU/hr.
Second, you need to tell us how big an area you want to cool, the insulation, and the climate. That will tell you the heat gain per hour .
For example, a typical 2000 sq ft ranch requires about 600–700 BTU/ hr per degree F. (Let’s say 600 BTU for easy math.) Now you need to know the Cooling Degree Days, CDD, for your area and we use 70 F as the base. If the temp is 90 F then that is 90–70=20 cooling degree days . Multiply by 600 BTU / hr and you get 12000 BTU/ hour. So a 12,000 BTU/hr air conditioner will cool your house to 20 F below the ambient. If the temp goes up to 100F your house will rise to 80F.
Is that cool enough? Maybe. I live in a cold climate and only use a 6000 BTU / hour unit.
You might have a larger house with poor insulation and need 1000 BTU /hr to maintain temp. You can get climate data from weather underground .
With that information you can decide how much you need.

SEER rating is the efficiency rating. The higher the number the less energy it takes to make the rated BTU / hr. SEER 10 was the minimum but that was recently increased to 12 (or 12.6).
A word of caution: the units made in China are notorious for only meeting specs over a very limited temp and humidity range. Two years ago a pile of them were sold at fire sale prices because they were rated at SEER 9.8. People bought them from a certain big box store for only $60. (In my opinion they got ripped off.)
Stay cool.

I would love to help you buy a new air conditioner, but I can’t afford it.