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Heat Gain and Loss Calculator

Heat Transfer Equation:

\[ Q = U \times A \times \Delta T \]

BTU/h-ft²-°F
square feet
°F

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1. What is the Heat Transfer Equation?

The heat transfer equation (Q = U × A × ΔT) calculates the rate of heat gain or loss through a building surface. It's fundamental for HVAC design, insulation evaluation, and energy efficiency calculations.

2. How Does the Calculator Work?

The calculator uses the heat transfer equation:

\[ Q = U \times A \times \Delta T \]

Where:

Explanation: The equation shows that heat transfer increases with higher U-values (poorer insulation), larger surface areas, and greater temperature differences.

3. Importance of Heat Transfer Calculation

Details: Accurate heat transfer calculations are essential for proper HVAC system sizing, energy efficiency assessments, building code compliance, and insulation effectiveness evaluation.

4. Using the Calculator

Tips: Enter U-value in BTU/h-ft²-°F, area in square feet, and temperature difference in °F. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is U-value?
A: U-value measures how well a building element conducts heat. Lower values indicate better insulation.

Q2: How does this relate to R-value?
A: R-value is insulation's resistance to heat flow (R = 1/U). Higher R-values mean better insulation.

Q3: What's a typical U-value for windows?
A: Single-pane windows might be 1.0-1.2, while double-pane low-e windows can be 0.3-0.5.

Q4: How to calculate annual heat loss?
A: Multiply hourly heat loss by heating degree days and hours per day, adjusting for thermostat settings.

Q5: Does this account for air infiltration?
A: No, this calculates conductive heat transfer only. Air leaks require separate calculations.

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