well i dont know the watts n all...but my guard said its n 8KV...plus the maintanence person said it has a tractor engine in it.....LOL...for the size lemme tell u...
its like around 4.5 feet high...and around 5.5 feet in lenght...and around 4 feet wide..quite huge it is...fully automatic...u dont have to switch it on when the power goes off...it turns on by itself..
and they say its an 8KV...
i might be more...and u can be riight about it...maybe i m misinformed...but 15 KV seems too huge of power to run two splits...
my friend has a 5 KV....around half the size of mine...and he runs one ac, pc 5-6 savers....3 fans all at a time....
u may need to consider a professional, all we can share is our experience.