Daylight Factor

More about: Daylight Factor

What it calculates

The “Daylight Factor” calculator computes Daylight factor (average) in % from 8 parameters: room length (m), room width (m), ceiling height (m), window glazing area (m²), glazing light transmittance, visible sky angle (°), average surface reflectance, maintenance factor.

A calculation that accounts for local rules and regional norms.

Example calculation

With parameters Room length = 5 m, Room width = 4 m, Ceiling height = 2.7 m, Window glazing area = 3 m², Glazing light transmittance = 0.7, Visible sky angle = 65 °, Average surface reflectance = 0.5, Maintenance factor = 0.9 the result is 1.85 % (Average daylight factor formula (BRE); Russian code SP 52.13330 sets a minimum daylight factor of at least 0.5% for living rooms).

How to use

1. Enter room length, room width, ceiling height, window glazing area, glazing light transmittance, visible sky angle, average surface reflectance and maintenance factor — each field above is adjustable with a slider.
2. Daylight factor (average) (%) is calculated automatically as you type.
3. Check the worked example below to see the formula applied to real numbers.
4. Copy the result or bookmark this calculator.

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