Can all four 12,000 BTU heads operate at the same time?

The indoor units all get their power from the outdoor unit. So as long as the breaker for the outdoor unit is properly sized it will be enough power for all of the indoor units as well. A 40amp breaker is perfect for this system. All of the indoor units can run simultaneously with no issues. These units are also very efficient and help to conserve power. For any more assistance, please give us a call.