Delta T describes a difference in which property?

Delta T describes a difference in which property?

• A. Pressure difference
• B. Humidity difference
• C. Temperature
• D. Volume difference

Answer: (C)

Delta T describes the difference between two temperatures—the change in temperature from one state to another. In building systems and heat transfer, this temperature difference is what drives energy exchange—for example, the difference between supply air and room air, or outdoor and indoor temperatures. This ΔT is central to calculations of heat transfer, such as how much energy moves as air passes through a coil. It’s not a measure of pressure, humidity, or volume, which are described by ΔP, ΔRH, and ΔV. For a concrete example, if air enters a cooling coil at 90°F and leaves at 70°F, the ΔT is 20°F.

Delta T describes the difference between two temperatures—the change in temperature from one state to another. In building systems and heat transfer, this temperature difference is what drives energy exchange—for example, the difference between supply air and room air, or outdoor and indoor temperatures. This ΔT is central to calculations of heat transfer, such as how much energy moves as air passes through a coil. It’s not a measure of pressure, humidity, or volume, which are described by ΔP, ΔRH, and ΔV. For a concrete example, if air enters a cooling coil at 90°F and leaves at 70°F, the ΔT is 20°F.