Recessed Lighting Calculator

Number of Lights Formula:

\[ \text{Number of Lights} = \frac{FC \times \text{Area}}{\text{Lumens per Light}} \]

Number of Lights Needed:

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1. What is a Recessed Lighting Calculator?

Definition: This calculator estimates the number of recessed lights needed based on desired illuminance, room area, and light output.

Purpose: It helps homeowners and electricians determine proper lighting placement for optimal illumination.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ \text{Number of Lights} = \frac{FC \times \text{Area}}{\text{Lumens per Light}} \]

Where:

\( FC \) — Desired illuminance in foot-candles (fc)
\( \text{Area} \) — Room area in square feet (ft²)
\( \text{Lumens per Light} \) — Light output of each fixture (lumens)

Explanation: The total required lumens (FC × Area) is divided by the output of each light to determine how many fixtures are needed.

3. Importance of Proper Lighting Calculation

Details: Correct lighting ensures adequate illumination for tasks, creates desired ambiance, and optimizes energy efficiency.

4. Using the Calculator

Tips: Enter desired illuminance (default 30 fc for general rooms), room area in square feet, and lumens per light (default 800 lm). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical FC value for different rooms?
A: Living rooms: 10-20 fc, Kitchens: 30-40 fc, Bathrooms: 70-80 fc, Offices: 50-75 fc.

Q2: How do I find lumens per light?
A: Check the product specifications - common values: 650 lm (60W equivalent), 1100 lm (75W), 1600 lm (100W).

Q3: Should I round up or down?
A: Always round up to ensure adequate lighting. Our calculator does this automatically.

Q4: Does this account for light loss factors?
A: No, consider multiplying by 1.2-1.5 for factors like fixture efficiency and room reflectance.

Q5: How do I space the lights?
A: Divide ceiling height by 2 for spacing in feet (e.g., 8 ft ceiling → lights 4 ft apart).