How many watts of lighting per square metre should a factory shop floor use?
BEE's MSME guidelines, drawing on the Energy Conservation Building Code, give lighting power density ranges of 6.0 to 12.0 W per square metre for process shop floors lit to 150 to 300 lux, 7.1 to 14.1 for workshops, 3.5 to 7.08 for warehouses and 5.0 to 9.5 for office buildings.
The ranges
- Administrative building, 50 to 400 lux: 5.0 to 9.5 W per square metre
- Administrative corridor, 100 lux: 2.3 to 7.1
- Shop floor process lighting, 150 to 300 lux: 6.0 to 12.0
- Workshop, 150 to 300 lux: 7.1 to 14.1
- Warehouse storage area, 100 to 150 lux: 3.5 to 7.08
How to work out yours
Add up the rated watts of every fitting in the area, including drivers or ballasts, and divide by the floor area in square metres. Then check the light level with a lux meter: a low figure with dark corners is not a win.
If you are above the range
- Replace old tube lights, mercury vapour and metal halide fittings with LEDs.
- Re-space fittings to the task instead of lighting every square metre evenly.
- Add daylight and controls; BEE also suggests solar tubes and solar PV lighting where feasible.
Example: a 1,000 square metre shop floor (illustrative)
- Before: 100 fittings of 150 W = 15,000 W; 15,000 / 1,000 = 15 W per square metre, above the 6.0 to 12.0 range
- After: 100 LED high-bays of 90 W = 9,000 W; 9 W per square metre, inside the range
- At 3,000 hours a year the change saves 6 kW x 3,000 = 18,000 kWh
Wattages and hours are illustrative. Confirm the light level on the floor after the change.
What Senseible does here
Senseible reads your electricity bills month by month, so an 18,000 kWh a year cut shows up in the record without anyone keying it in.
Last reviewed 2026-10-24.