What temperature differential should makeup air not exceed in a conditioned space?

Makeup air in a conditioned space plays a crucial role in maintaining indoor air quality and the efficiency of the HVAC system. The temperature differential that makeup air should not exceed is important because a significant temperature difference can lead to discomfort, energy inefficiency, and strain on the heating and cooling systems.

The correct answer, a maximum differential of 10°F, is based on standards that aim to ensure that the temperature of the incoming makeup air remains close to that of the indoor environment. When the temperature of the makeup air is kept within this range, it helps to maintain a balanced and comfortable indoor climate, minimizing energy costs and wear and tear on HVAC equipment, which would work harder if the air temperature differential were larger.

If the differential were higher, it could result in unwanted drafts, temperature stratification, and an increased need for heating or cooling, thereby reducing the overall efficiency and comfort of the space. This is why maintaining a 10°F differential is a standard guideline in the North Carolina Mechanical Code and similar regulations, ensuring proper air quality management while promoting energy efficiency.