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BTU/h Formula:
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The CFM to BTU conversion calculates heating or cooling capacity based on airflow and temperature difference. This formula is essential for HVAC system design, sizing equipment, and energy efficiency calculations in heating, ventilation, and air conditioning applications.
The calculator uses the BTU/h formula:
Where:
Explanation: The constant 1.08 combines the specific heat of air (0.24 BTU/lb·°F) and the density of standard air (0.075 lb/ft³), multiplied by 60 minutes per hour.
Details: Accurate BTU calculation is crucial for proper HVAC system sizing, energy efficiency optimization, comfort control, and preventing equipment oversizing or undersizing which can lead to energy waste and poor performance.
Tips: Enter CFM value (must be positive) and temperature difference in °F. The temperature difference is typically the difference between supply air temperature and room air temperature for cooling, or vice versa for heating.
Q1: What does the constant 1.08 represent?
A: The constant 1.08 accounts for the specific heat of air (0.24 BTU/lb·°F) and standard air density (0.075 lb/ft³), multiplied by 60 minutes per hour: 0.24 × 0.075 × 60 = 1.08.
Q2: Can this formula be used for both heating and cooling?
A: Yes, the formula works for both heating and cooling applications. For heating, ΔT is positive (supply air warmer than room), for cooling, ΔT is negative (supply air cooler than room).
Q3: What are typical CFM values for residential systems?
A: Typical residential systems range from 400-2000 CFM depending on home size, with 1 CFM per square foot being a common rule of thumb for sizing.
Q4: Does this account for humidity?
A: No, this basic formula only accounts for sensible heat. For latent heat (humidity) calculations, additional factors are needed.
Q5: How accurate is this calculation?
A: This provides a good estimate for standard conditions. Actual performance may vary with altitude, humidity, and specific air properties.