How hot should air be out of heater ducts?

The air coming out of heater ducts typically should be between 120°F to 160°F (49°C to 71°C) for optimal heating comfort. However, this can vary based on the type of heating system used and the specific requirements of the space being heated. It's essential to ensure that the air temperature is comfortable without causing burns or discomfort. If the air temperature falls outside this range, it may indicate a problem with the heating system.