https://gensizer.assurancepower.com/...ouse&Itemid=55

A Load calculator for generator sizing. I put some numbers in quick. Figured on a 3 ton Ac. Came out as 22kw. To meet code with an automatic transfer switch for the whole house you either need to size generator to load calc or rent a power logger for 30 days to see what your peak kw was. I don't know if you power company can give you that information or not.