1. What is a Heat Loss Calculator?

Definition: This calculator estimates the heat loss in watts through a building element based on U-value, surface area, and temperature difference.

Purpose: It helps architects, engineers, and energy assessors determine heat transfer rates for building insulation and heating system design.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Heat loss (watts)
• \( U \) — U-value (W/m²K)
• \( A \) — Surface area (m²)
• \( \Delta T \) — Temperature difference (Kelvin)

Explanation: The U-value represents thermal transmittance, multiplied by the surface area and temperature difference to calculate total heat flow.

3. Importance of Heat Loss Calculation

Details: Accurate heat loss calculations are essential for energy-efficient building design, proper heating system sizing, and compliance with building regulations.

4. Using the Calculator

Tips: Enter the U-value (thermal transmittance), surface area in square meters, and temperature difference in Kelvin. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical U-value for walls?
A: Modern insulated walls typically have U-values between 0.15-0.30 W/m²K, while older walls may be 1.0-2.0 W/m²K.

Q2: How do I convert Celsius to Kelvin?
A: The temperature difference in Kelvin is numerically equal to the difference in Celsius (ΔT in K = ΔT in °C).

Q3: What's the difference between U-value and R-value?
A: U-value measures heat transfer (lower is better), while R-value measures resistance to heat flow (higher is better). U = 1/R.

Q4: Should I calculate for each building element separately?
A: Yes, calculate heat loss separately for walls, windows, roof, etc., then sum the results for total building heat loss.

Q5: Does this include ventilation heat loss?
A: No, this calculates fabric heat loss only. Ventilation heat loss requires additional calculations based on air changes.