1. What is Cooling Load Heat Gain through Windows?

Definition: This calculator estimates the sensible cooling load from heat gain through windows based on glass area and glass load factor.

Purpose: It helps HVAC professionals and engineers determine the cooling requirements for spaces with significant window areas.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Sensible cooling load (Watts)
• \( A_{glass} \) — Area of glass (square meters)
• \( GLF \) — Glass load factor (Watts/square meter)

Explanation: The heat gain through windows is calculated by multiplying the window area by the glass load factor which accounts for both solar radiation and conduction.

3. Importance of Window Heat Gain Calculation

Details: Proper calculation ensures adequate HVAC system sizing, energy efficiency, and occupant comfort in buildings with significant glazing.

4. Using the Calculator

Tips: Enter the glass area in m², glass load factor in W/m², and optional tolerance percentage (±5%). All values must be positive except tolerance which can be negative.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical glass load factor?
A: GLF varies by window type, orientation, shading, and climate but typically ranges from 50-250 W/m².

Q2: How do I measure glass area?
A: Measure the height and width of each window and calculate the total area of all windows in the space.

Q3: What does the tolerance percentage do?
A: It allows you to add (±5%) safety margin to account for variations in conditions or conservative design.

Q4: Does this include conductive and radiative heat?
A: Yes, the GLF should account for both solar radiation and conduction through the glass.

Q5: How does window orientation affect the calculation?
A: Orientation affects solar gain and should be reflected in the GLF value used (higher for south-facing in northern hemisphere).

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