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Tepelné ztráty okny

Window Heat Loss Calculator

Window Width (m)
Window Height (m)
U-value (W/m²·K)
Temperature Diff ΔT (°C)
U-value: Single glazing ≈ 5.7 · Double ≈ 2.8 · Triple ≈ 0.8

✓Heat Loss

Plocha (m²)
1.80
Heat Loss (W)
100.8
Annual Cost (est.)
$65.32
Annual Heating Energy (kWh)
435.5 kWh

What is Window Heat Loss?

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Kalkulátor tepelných ztrát oken odhaduje ztrátu tepelné energie okny na základě jejich hodnoty U (prostup tepla), plochy a teplotního rozdílu mezi vnitřní a vnější teplotou.

Calkulon makes complex calculations simple — built for students and everyday problem-solvers.

Vzorec

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f(x)Tepelné ztráty (W) = U-hodnota × plocha (m²) × ΔT (°C) | Jedna tabule U≈5,9; Dvojité sklo U≈2,8; Trojité sklo U≈0,9 W/m²K

How to Window Heat Loss

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  1. 1Heat loss (W) = U-value × Area (m²) × ΔT (°C)
  2. 2U-value: single glazing ~5.8; double ~2.8; triple ~1.1 W/m²·K
  3. 3ΔT = Indoor temp − Outdoor temp (°C)
  4. 4Annual heat loss (kWh) = W × Hours/season / 1,000

Worked Examples

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Example 1
Given:5m² double glazing (U=2.8), 20°C inside, 0°C outside
Výsledek:Heat loss = 2.8 × 5 × 20 = 280W; annual (3,000 heating hours) = 840 kWh

Real-World Applications

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Academic homework and exam preparation

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Engineering and architecture calculations

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Everyday measurement tasks around the home

Window U-Values

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Glazing typeU-value (W/m²·K)Energy rating (UK)
Single glazing~5.8F or below
Standard double~2.8C–D
A-rated double~1.6A
Triple glazing~0.8–1.1A+

Frequently Asked Questions

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Q

What is Window Heat Loss?

A

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. Use this calculator for accurate, instant results.

Q

How accurate is the Window Heat Loss calculator?

A

The calculator uses the standard published formula for window heat loss. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.

Q

What units does the Window Heat Loss calculator use?

A

This calculator works with inches, square metres, Celsius, kilowatts. You can enter values in the units shown — the calculator handles all conversions internally.

Q

What formula does the Window Heat Loss calculator use?

A

The core formula is: Heat loss (W) = U-value × Area (m²) × ΔT (°C). Each step in the calculation is shown so you can verify the result manually.

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HVAC Sizing vs Window Heat Loss

Formula-verified for precision
Reviewed October 2026
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