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BTU Heating Equation:
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The BTU (British Thermal Unit) heating equation calculates the heating capacity required for a space based on airflow and temperature difference. It's commonly used in HVAC system design and analysis.
The calculator uses the BTU heating equation:
Where:
Explanation: The equation calculates the amount of heat energy (in BTU/hr) needed to raise the temperature of a given airflow by a specific temperature difference.
Details: Accurate BTU calculation is essential for proper HVAC system sizing, energy efficiency optimization, and ensuring comfortable indoor environments. It helps prevent undersizing (inadequate heating) or oversizing (energy waste and poor humidity control).
Tips: Enter CFM (cubic feet per minute) and temperature difference in °F. Both values must be positive numbers for meaningful results.
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 the density of standard air (0.075 lb/ft³), converted to hourly rate: 0.24 × 0.075 × 60 = 1.08.
Q2: When is this equation most accurate?
A: This equation is most accurate for standard air conditions at sea level (29.92 inHg, 70°F, 50% RH). Altitude and extreme conditions may require adjustments.
Q3: Can this be used for cooling calculations?
A: While similar principles apply, cooling calculations typically use 4.5 × CFM × Δh (where Δh is enthalpy difference) to account for both sensible and latent heat.
Q4: What are typical CFM values for residential systems?
A: Residential HVAC systems typically range from 400-2000 CFM depending on the size of the home and system capacity.
Q5: How does altitude affect the calculation?
A: At higher altitudes, air density decreases, so the constant 1.08 should be adjusted based on the actual air density at that elevation.