Question 1

What is a Window Heat Loss?

Accepted Answer

A window heat loss calculator estimates the thermal energy lost through windows based on their U-value (thermal transmittance), area, and the temperature difference between inside and outside.

Question 2

How does the Window Heat Loss work?

Accepted Answer

Heat loss (W) = U-value × Area (m²) × ΔT (°C) Then: U-value: single glazing ~5.8; double ~2.8; triple ~1.1 W/m²·K Then: ΔT = Indoor temp − Outdoor temp (°C) Then: Annual heat loss (kWh) = W × Hours/season / 1,000.

Question 3

Can you give an example of how to use the Window Heat Loss?

Accepted Answer

Example: Input 5m² double glazing (U=2.8), 20°C inside, 0°C outside gives a result of Heat loss = 2.8 × 5 × 20 = 280W; annual (3,000 heating hours) = 840 kWh.

Question 4

Is the Window Heat Loss free to use?

Accepted Answer

Yes — completely free with no registration, download, or subscription required. All calculations happen instantly in your browser.

Question 5

How accurate is the Window Heat Loss?

Accepted Answer

Our Window Heat Loss uses verified mathematical formulas and is accurate to multiple decimal places. Results are calculated in real-time using the same methods used by professionals.

Window Heat Loss

Window Heat Loss Calculator

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What is Window Heat Loss?

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Example Window Heat Loss Examples

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