Your are likely going to need two 240V 45AMP circuits installed. A whole house surge protector is recommended also, as 240V surge protectors for high AMP devices are much more expensive than using a single whole house protector. You would likely need 200AMP mains service to support this along with your normal needs, which not all house have. Best bet is going to be calling up a electrician and them come out to give a quote.
why do you need two 45 amp circuits?
2100 watts at 240 volts is 9 amps... you won't need two circuits... one will do.
however, if you're using 120 volts... then you'll need two circuits, because 18 Amps continuous draw is higher than the average household breaker.
