Use ASHRAE data to determine which will be the most economical to operate. They both use the same major components.
Being a technician, I would always pick Trane over Carrier, only because Carrier seems to be always "reinventing the wheel" when engineering their electronic controls. Consider also ICP (now owned by Carrier). ICP brands include Heil, Tempstar and Sears. Excellent equipment. Carrier has not yet micromanaged ICP's design/ engineering departments out of bulletproof design practices.
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