How do you calculate the required CFM for an HVAC system?

Prepare for the Master Mechanical License Test with flashcards and multiple-choice questions. Each question includes hints and detailed explanations. Get confident for your exam!

To calculate the required CFM (Cubic Feet per Minute) for an HVAC system, the correct approach involves using the formula that incorporates the system's BTU (British Thermal Units) per hour and the temperature difference (ΔT) between the supply air and the return air. This specific formula, CFM = BTU/hr ÷ (1.08 × ΔT), provides an accurate means to determine the airflow needed to effectively heat or cool a space.

The factor of 1.08 in the formula accounts for the density of air and the specific heat of water, making it crucial for ensuring that the calculation delivers a precise airflow rate based on the heating or cooling requirements of the space. As such, applying this formula allows professionals to tailor the HVAC system effectively to meet the thermal demands of the environment, ensuring both efficiency and comfort.

While options discussing duct measurements, consulting reference tables, and considering the size of the heating element may provide relevant information, they do not directly establish the necessary airflow rate as effectively as the formula does.

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