1. What is a Room Lighting Calculator?

Definition: This calculator determines the total lumens required to achieve a desired lighting level (in foot-candles) for a given room area.

Purpose: Helps architects, interior designers, and homeowners properly illuminate spaces according to recommended lighting standards.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• Lumens — Total light output needed (lm)
• FC — Desired illuminance level (foot-candles)
• Area — Room area in square feet (ft²)

Explanation: The desired illuminance (in foot-candles) is multiplied by the room area to determine the total lumens required.

3. Importance of Proper Lighting Calculation

Details: Correct lighting calculations ensure adequate illumination for tasks, enhance room aesthetics, and improve energy efficiency by preventing over-lighting.

4. Using the Calculator

Tips: Enter the desired foot-candle level (see reference values below) and room area in square feet. All values must be > 0.

Typical FC Requirements:

• General residential: 10-20 fc
• Kitchen work areas: 30-40 fc
• Office workspace: 30-50 fc
• Retail spaces: 50-75 fc
• Detailed work (sewing, drafting): 75-100 fc

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between lumens and foot-candles?
A: Lumens measure total light output, while foot-candles measure light falling on a surface (illuminance).

Q2: How do I convert lumens to watts?
A: Divide lumens by the efficacy (lumens per watt) of your light source (LED: ~80-100 lm/W, CFL: ~50-70 lm/W, Incandescent: ~10-17 lm/W).

Q3: Should I account for light loss factors?
A: Yes, consider adding 20-30% to the calculated lumens to account for fixture efficiency, dirt accumulation, and light depreciation over time.

Q4: How does room color affect lighting needs?
A: Dark-colored rooms may need 10-20% more lumens, while light-colored rooms may reflect more light and require slightly less.

Q5: How many fixtures do I need?
A: Divide total lumens by the lumen output per fixture (check product specifications) to determine the number of fixtures required.