A 12000 sqft home would probaly use more than 1 unit.
Area
What size of central and heat unit do you need for 916 sq ft?
To find the area of a book cover in metric units, the most appropriate unit to use would be centimeters. The formula for finding the area of a book cover would be: length x width.
i would use a 2 1/2 ton no higher than a 3 ton unit.
I would first make the decision as to how much square footage you except the air conditioner to cover. If it is a normal size square footage I would base your purchase on that.
centimeter
048 would be a 4 ton unit
1800 btus
meters2
A 2 ton unit would be most useful for that size home. 1280SF generator will be most useful and cost less in the long run. It will also last longer because it can hold up to what is needed.
that would be the centimetre