My unit is brand new, well about 2 months old and everything has been working fine but now every time the outside unit turns ON it sounds really loud at startup then works quietly/normal, it's just when it starts up that it makes the loud starting noise.

One more thing, the unit is a seer 13, 3 ton and supposedly more efficient than the one I replace but the month that the old one went bad we were without AC for about 5 days and the electric bill went up dramatically about $200 more than usual.

*The old unit was a seer 11, 3 ton

Seeing that this is a new unit I'd contact the installer and have them come back to look at this at no cost. Shouldn't act like that.

Does this new unit keep running and not cooling down the house properly? For the electric to jump that much sounds like it's pulling too much power somewhere.

It does cool the house really well but it's just when it turns on it gives a loud startup noise.

I will try and get the installer back to check it. On the electrical I have not made any additions besides the AC unit since the high bill but I had the electrical company check and replace the meter just in case.