Average Daylight Factor Calculator

Average Daylight Factor Formula:

\[ ADF = \frac{\sum (DF_i \times A_i)}{\sum A_i} \]

Average Daylight Factor (ADF):

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1. What is Average Daylight Factor?

The Average Daylight Factor (ADF) is a metric used in architectural lighting design to quantify the average amount of natural daylight available in a space. It represents the ratio of indoor illuminance to outdoor illuminance, expressed as a percentage.

2. How Does the Calculator Work?

The calculator uses the area-weighted average formula:

\[ ADF = \frac{\sum (DF_i \times A_i)}{\sum A_i} \]

Where:

\( ADF \) — Average Daylight Factor (%)
\( DF_i \) — Daylight Factor for each area (%)
\( A_i \) — Area of each section (m²)

Explanation: The formula calculates the weighted average of daylight factors across different areas, where each daylight factor is weighted by its corresponding area.

3. Importance of ADF Calculation

Details: ADF is crucial for evaluating building energy performance, ensuring adequate natural lighting, and meeting building code requirements for daylighting in sustainable building design.

4. Using the Calculator

Tips: Enter daylight factor values and corresponding area values as comma-separated lists. Ensure both lists have the same number of values and all values are positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a good ADF value?
A: Generally, ADF values of 2-5% are considered good for most spaces, with higher values indicating better daylight availability.

Q2: How is daylight factor measured?
A: Daylight factor is typically measured using specialized equipment or calculated through computer simulations based on window size, orientation, and external obstructions.

Q3: Why use area-weighted average?
A: Area-weighting ensures that larger spaces have proportionally greater influence on the overall average, providing a more accurate representation of the entire area.

Q4: What factors affect daylight factor?
A: Window size, glazing type, room geometry, external obstructions, surface reflectances, and geographical location all influence daylight factor values.

Q5: Is ADF used in building regulations?
A: Yes, many building codes and sustainability standards (like LEED, BREEAM) include ADF requirements for daylighting compliance.