8.33 amps per kilowatt at 120 volts
4.5 amps per kilowatt at 240 volt
30 amp fuse use #10 wire
20 amp fuse use #12 wire
Since you dont use the the air condition and heater at the same time. They can be on the same circuit size your fuse for the heater and dont worry about the a/c.
1600...