In a conditioned space, makeup air temperature must not differ from the room temperature by more than how many degrees Fahrenheit?

In a conditioned space, makeup air temperature must not differ from the room temperature by more than how many degrees Fahrenheit?

• A. 8 °F
• B. 10 °F
• C. 12 °F
• D. 14 °F

Answer: (B)

Maintaining makeup air within a narrow temperature range of the room air keeps comfort and system balance intact. When makeup air—air brought in to replace exhausted air—has a temperature far from the space air, it can create noticeable drafts and hot or cold spots near vents or entry points. It also makes the HVAC system work harder to temper that air to the room temperature, increasing energy use and potentially affecting humidity and overall comfort. A practical guideline for conditioned spaces is that makeup air should not differ from room temperature by more than ten degrees Fahrenheit. This keeps the incoming air close enough to room conditions so mixing stabilizes quickly and doesn’t disrupt occupants or the space’s thermal harmony. If the difference were smaller, like eight degrees, it would be more restrictive than needed in many cases. If it were larger, such as twelve or fourteen degrees, the risk of drafts and comfort issues rises, and the system would incur higher tempering loads.

Maintaining makeup air within a narrow temperature range of the room air keeps comfort and system balance intact. When makeup air—air brought in to replace exhausted air—has a temperature far from the space air, it can create noticeable drafts and hot or cold spots near vents or entry points. It also makes the HVAC system work harder to temper that air to the room temperature, increasing energy use and potentially affecting humidity and overall comfort.

A practical guideline for conditioned spaces is that makeup air should not differ from room temperature by more than ten degrees Fahrenheit. This keeps the incoming air close enough to room conditions so mixing stabilizes quickly and doesn’t disrupt occupants or the space’s thermal harmony.

If the difference were smaller, like eight degrees, it would be more restrictive than needed in many cases. If it were larger, such as twelve or fourteen degrees, the risk of drafts and comfort issues rises, and the system would incur higher tempering loads.