I have to use the central air in summer constantly because the 100 plus degrees everyday. I have installed a window a/c 15000 btu, 15 amps. The question is if I would be overloading the system in the house using both at the same time. The purpose of both working would be using less the central unit that takes so much power to operate. Thank you for any answers..As you can see, I don't know anything about electricity. Thank you again.