Final answer:
The ideal temperature difference between supply air and return air in an A/C system is typically 14-22°F. This range ensures efficient operation of the system.
Step-by-step explanation:
The variation in temperature between the supply air and the return air in an A/C system should be approximately 14-22°F. This temperature difference is critical to ensure that the system is performing efficiently and effectively transferring heat. In an average residential or commercial system, this is the range you would expect if the system is properly sized and functioning as intended.