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BTU to CFM Formula:
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The BTU to CFM formula calculates the required airflow (in cubic feet per minute) needed to transfer a specific amount of heat energy (in British Thermal Units per hour) given a temperature difference. This is essential for HVAC system design and sizing.
The calculator uses the BTU to CFM formula:
Where:
Explanation: The constant 1.08 accounts for the specific heat of air (0.24 BTU/lb·°F) and the density of air (0.075 lb/ft³) at standard conditions.
Details: Proper airflow calculation is crucial for designing efficient HVAC systems, ensuring adequate heating/cooling capacity, maintaining indoor air quality, and optimizing energy efficiency in residential and commercial buildings.
Tips: Enter BTU/hr value (positive number), temperature difference in °F (positive number). Both values must be greater than zero for accurate calculation.
Q1: What does the constant 1.08 represent?
A: The constant 1.08 is derived from the product of air density (0.075 lb/ft³) and specific heat of air (0.24 BTU/lb·°F) multiplied by 60 minutes.
Q2: When is this formula typically used?
A: This formula is commonly used in HVAC design for sizing ductwork, selecting fans, and determining airflow requirements for heating and cooling systems.
Q3: What are typical CFM values for residential systems?
A: Residential systems typically range from 400-2000 CFM depending on the size of the home and the heating/cooling capacity required.
Q4: Does this formula work for both heating and cooling?
A: Yes, the formula works for both heating and cooling applications, as it calculates the airflow needed to transfer a specific amount of thermal energy.
Q5: What factors can affect the accuracy of this calculation?
A: Altitude, humidity, air density variations, and non-standard temperature conditions can affect the accuracy. The formula assumes standard air conditions at sea level.