Building Heat Loss Calculator

Heat Loss Formula:

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

U-Value (W/m²K):

Area (m²):

Temperature Difference (ΔT in K):

Ventilation Loss (W):

Infiltration Loss (W):

Total Heat Loss (W):

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1. What is a Building Heat Loss Calculator?

Definition: This calculator estimates the total heat loss of a building based on U-values, surface areas, temperature differences, and additional heat loss factors.

Purpose: It helps architects, engineers, and homeowners determine heating requirements and improve energy efficiency.

2. How Does the Calculator Work?

The calculator uses the formula:

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

Where:

\( Q \) — Total heat loss (Watts)
\( U \) — U-value (heat transfer coefficient in W/m²K)
\( A \) — Surface area (m²)
\( \Delta T \) — Temperature difference (Kelvin)
ventilation — Heat loss through ventilation (W)
infiltration — Heat loss through air infiltration (W)

Explanation: The calculator sums the conductive heat loss through building elements plus additional losses from ventilation and air infiltration.

3. Importance of Heat Loss Calculation

Details: Accurate heat loss calculations ensure proper heating system sizing, energy efficiency, and comfort while preventing over- or under-heating.

4. Using the Calculator

Tips: Enter U-value (lower is better insulation), surface area, temperature difference between inside and outside, and any additional ventilation or infiltration losses.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical U-value for walls?
A: Modern insulated walls typically have U-values between 0.1-0.3 W/m²K, while older walls may be 1.0-2.0 W/m²K.

Q2: How do I determine ΔT?
A: Subtract the outside design temperature from your desired indoor temperature (e.g., 20°C inside - (-5°C outside) = 25K ΔT).

Q3: What's the difference between ventilation and infiltration?
A: Ventilation is intentional air exchange, while infiltration is uncontrolled air leakage through cracks and gaps.

Q4: Should I include all building elements?
A: Yes, for accurate results calculate heat loss for walls, roof, floor, windows, and doors separately then sum them.

Q5: How can I reduce heat loss?
A: Improve insulation (lower U-values), reduce air leakage, install energy-efficient windows, and use heat recovery ventilation.