Carol, it looks to me like (IF) you really have to have 6CFM minimum at 90lbs, it will take more than your standard 20amp 110volt plug to do this.
The bigger 220volt 40 amp units can be a couple hundred pounds, and they are big. Taking up floor space.
With a bigger unit, you will have to invest in a dedicated 220 circuit, as well as the possibility of special electrical cutoffs like HVAC units use (depends on local code).
Yes you can wire it up yourself, if you know what you are doing, but it's probably better to hire an electrician to do it right.
All of the units will probably be made in China, but some will be closer in output to what their labels say than others.
What you might want to do is rent a compressor for a day that is 110 volt and at 20amps or less (if your home system can handle that much amperage)
If the rental is 5 CFM and that works fine, might as well save the money on buying such a huge compressor. the big ones will do 14CFM at 90, which is overkill for your needs.
Be cognoscente of overloading your electric system with 110V at 20amp compressors. If the compressor will not start, or keeps blowing the breaker, it is too big for your electrical system
Also, be wary of 220V machines coming in 3 Phase. You can't use those at home. That electrical service is not available to you. They should not be rewired to single phase either, because its easy to electrocute yourself with it then.
So in a nutshell I'd say, rent a tester machine, run it for a while under your intended load, if it works out buy that one, if not poney up and have an electrician wire you up for a 220volt single phase unit, which is much more expensive.
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