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HVAC BTU Calculator

HVAC BTU Equation:

\[ BTU/h = 1.08 \times CFM \times \Delta T \]

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°F

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1. What is the HVAC BTU Equation?

The HVAC BTU equation calculates the heat transfer rate in British Thermal Units per hour (BTU/h) based on airflow in cubic feet per minute (CFM) and temperature difference in degrees Fahrenheit (°F). This is fundamental for sizing HVAC equipment and assessing system performance.

2. How Does the Calculator Work?

The calculator uses the basic HVAC equation:

\[ BTU/h = 1.08 \times CFM \times \Delta T \]

Where:

Explanation: The equation calculates how much heat energy is being moved by the air in an HVAC system per hour.

3. Importance of BTU Calculation

Details: Accurate BTU calculation is essential for proper HVAC system sizing, energy efficiency analysis, and troubleshooting system performance issues.

4. Using the Calculator

Tips: Enter CFM (airflow) and ΔT (temperature difference between supply and return air). Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the significance of the 1.08 constant?
A: It combines the specific heat of air (0.24 BTU/lb-°F) and standard air density (0.075 lb/ft³), with conversion factors for minutes to hours.

Q2: How accurate is this calculation?
A: It's accurate for standard air conditions. For high altitude or extreme temperatures, adjustments may be needed.

Q3: Can I use this for cooling calculations?
A: Yes, the same equation applies for both heating and cooling BTU calculations.

Q4: What's a typical ΔT for residential systems?
A: Typically 15-20°F for heating, 18-22°F for cooling, but varies by system design.

Q5: How does this relate to tonnage?
A: 1 ton of cooling = 12,000 BTU/h. Divide BTU/h by 12,000 to get cooling tons.

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