Calculate Heat Loss Of House

Heat Loss Equation:

\[ Q = \sum (U \times A \times \Delta T) + \text{Infiltration} \]

U-Value:

BTU/hr·ft²·°F

Area:

ft²

Temperature Difference (ΔT):

°F

Infiltration Heat Loss:

BTU/hr

Total Heat Loss (Q):

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1. What Is Heat Loss Calculation?

Heat loss calculation determines the amount of heat energy that escapes from a building through its envelope (walls, windows, roof, etc.) and air infiltration. This calculation is essential for proper HVAC system sizing and energy efficiency analysis.

2. How Does The Calculator Work?

The calculator uses the heat loss equation:

\[ Q = \sum (U \times A \times \Delta T) + \text{Infiltration} \]

Where:

\( Q \) — Total heat loss (BTU/hr or W)
\( U \) — U-value, thermal transmittance (BTU/hr·ft²·°F or W/m²K)
\( A \) — Surface area (ft² or m²)
\( \Delta T \) — Temperature difference between inside and outside (°F or K)
\( \text{Infiltration} \) — Heat loss due to air leakage (BTU/hr or W)

Explanation: The equation calculates heat transfer through building components and adds infiltration losses to determine total building heat loss.

3. Importance Of Heat Loss Calculation

Details: Accurate heat loss calculation is crucial for proper HVAC system design, energy efficiency improvements, building code compliance, and reducing energy costs while maintaining occupant comfort.

4. Using The Calculator

Tips: Enter U-value in BTU/hr·ft²·°F, area in square feet, temperature difference in °F, and infiltration heat loss in BTU/hr. 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 U-values indicate better insulation properties and reduced heat transfer.

Q2: How Is Temperature Difference Determined?
A: ΔT is the difference between desired indoor temperature and design outdoor temperature for your climate zone.

Q3: What Factors Affect Infiltration Heat Loss?
A: Air tightness, wind speed, building height, number of openings, and quality of construction affect infiltration rates.

Q4: Why Calculate Heat Loss For Multiple Surfaces?
A: Different building components (walls, windows, roof) have different U-values and areas, requiring separate calculations summed together.

Q5: How Accurate Are These Calculations?
A: While simplified, this method provides good estimates for residential applications. Professional energy audits may use more detailed methods.