Cars & Other Vehicles Which wire is better for AC? Which wire is better for AC? With their superior energy efficiency and consequent savings in monthly power bills, the AC with Copper Condensing Coil is a much better. Copper has a heat transfer coefficient above aluminum. Copper is a better device than aluminium. Related Posts:How to tell if you have a faulty coil pack is one of the symptoms.What is the maximum Amp Ratings for 70, 80, 100, 125, 150, 200, 400, 600 Amp wire and breaker chart?What gauge of wire do you use for a 20 Amp outlet?How do I wire a 3 way switch with red and black?