answer: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.