1. What is Heat Loss Calculation?

Heat loss calculation estimates the amount of heat energy that escapes from a building or system. It's essential for proper HVAC system sizing and energy efficiency assessments.

2. How Does the Calculator Work?

The calculator uses the heat loss equation:

Where:

• \( Q \) — Total heat loss (BTU/hr)
• \( A_i \) — Surface area (ft²)
• \( U_i \) — U-value of the material (BTU/hr-ft²-°F)
• \( \Delta T \) — Temperature difference between inside and outside (°F)
• \( \text{infiltration} \) — Additional heat loss from air leaks (BTU/hr)

Explanation: The equation calculates conductive heat loss through building surfaces plus any additional losses from air infiltration.

3. Importance of Heat Loss Calculation

Details: Accurate heat loss calculation is crucial for proper HVAC system sizing, energy efficiency improvements, and thermal comfort assessment.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What is a typical U-value for walls?
A: Modern insulated walls typically have U-values between 0.03-0.07 BTU/hr-ft²-°F, while older walls may be 0.1-0.3.

Q2: How do I account for multiple surfaces?
A: Calculate each surface separately and sum the results, or use specialized software for complex buildings.

Q3: What's a reasonable temperature difference (ΔT)?
A: For residential heating, typically 50-70°F (indoor 70°F, outdoor 0-20°F in winter).

Q4: How do I estimate infiltration losses?
A: Professional energy audits use blower door tests, but rough estimates can be 10-30% of conductive losses.

Q5: Are there other heat loss mechanisms?
A: Yes, including radiation and ground contact losses, which require more complex calculations.