Heat Loss Formula:
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Definition: This calculator estimates heat loss through building elements using the basic heat transfer equation.
Purpose: It helps heating engineers and building professionals determine the heat loss for proper radiator sizing.
The calculator uses the formula:
Where:
Explanation: The U-value represents thermal transmittance, multiplied by the area and temperature difference to calculate heat flow.
Details: Accurate heat loss calculations ensure properly sized heating systems, energy efficiency, and comfortable indoor environments.
Tips: Enter the U-value of the building element, its surface area, and the temperature difference between inside and outside. All values must be > 0.
Q1: What are typical U-values?
A: Modern walls: 0.18-0.30 W/m²K, Windows: 1.2-2.8 W/m²K, Roofs: 0.13-0.25 W/m²K depending on construction.
Q2: How do I determine ΔT?
A: Subtract the design external temperature from your desired internal temperature (e.g., 21°C inside - (-3°C outside) = 24K.
Q3: Does this account for ventilation losses?
A: No, this calculates fabric heat loss only. Ventilation losses should be calculated separately and added.
Q4: Why use Kelvin for temperature difference?
A: The Kelvin scale gives the same magnitude as Celsius for differences (1K = 1°C difference).
Q5: How accurate is this basic calculation?
A: It provides a good estimate but professional heat loss calculations consider more factors like thermal bridging.