What is Lumen? How to Convert Lumens to Watts? What Are the Best Lumens for Office Lighting?
- 13 Feb 2025
Lighting supports our circadian rhythm, stabilizes mood, and lowers visual fatigue through spectral distribution.
High CRI fixtures improve color accuracy and task performance in detail-oriented settings. Flicker-free drivers diminish headaches and eye strain to keep the work environment comfy. Glare control decreases eye stress via optimized fixture placement and lens technology. Color temperature tuning (cool white by day, warm white by evening) helps keep alertness and healthy sleep patterns.
Valuing lumens to watts assures efficient power usage with illumination levels for focus and comfort. Control strategies, including dimming and daylight integration, boost well-being and productivity while adjusting light intensity to user needs.
Lighting performance is typically determined by all the metrics, and in this blog, we primarily introduce Lumen.
What is a Lumen and Watts?
A lumen (lm) specifies the luminous flux a light source emits. It focuses on human visual sensitivity to wavelengths. A watt (W) measures electrical power consumption. It is independent of whether that power converts into visible light or wasted heat. High-end photometry labs use an integrated sphere or goniophotometer to quantify lumens. They track how much visible energy spreads across angles. In contrast, watts are measured with standard power meters. They gauge voltage and current without reflecting how bright the lamp appears.
Difference between Lumens and Watts
People once judged brightness by watts. That made sense when incandescent bulbs dominated because higher wattage meant more lumens. Contemporary lighting upended that correlation. LEDs and fluorescent lamps deliver more lumens per watt than incandescent. Their luminous efficacy can be 50-110 lumens/W. Old tungsten filaments rarely pass 18 lumens/W. So, direct lumens to watts comparisons can be misleading if someone equates power draw with brightness.
Source： https://www.sciencedirect.com/topics/engineering/luminous-efficacy
Lumen to Watt Conversion Guide
The Lumen to Watt Formula is:
Watts (W) = Lumens (lm) ÷ Lumens Per Watt (lm/W)
A “lumens to watts” formula is impossible without a luminous efficacy, how well a light source converts energy (watts) into light (lumens).
Lamp type | Luminous efficacy (lm/W) | Lifetime of lamp (h) | Colour rendering index |
Incandescent | 12–35 | 2000–4000 | 100 |
Fluorescent | 50–100 | 10,000–16,000 | 90 |
CFL | 40–75 | 6000–12000 | 80 |
LED | 20–150 | 20,000–100,000 | 80 |
Source: https://www.sciencedirect.com/topics/engineering/luminous-efficacy
Here are the basic equations for each major bulb type
- LED: Watts = Lumens / 80
- CFL: Watts = Lumens / 70
- Halogen: Watts = Lumens / 20
- Incandescent: Watts = Lumens / 15
For instance, 800 lumens from an LED might mean 10 W. On the other hand, an incandescent would need around 53.3 W for the same luminous flux.
Why Lumens Matter
Human brightness perception depends on the lumens striking the eye within sensitivity bands. Two sources emitting identical lumens to watts ratios can appear differently bright if one skews output toward human peak sensitivity. Even small changes in luminous intensity at these wavelengths can produce large shifts in perceived brightness. That’s why raw lumen numbers sometimes need weighting factors for more precise psycho-visual matching.
In professional settings, specifying correct lumen levels is important. Overly high luminous flux can cause glare for eye fatigue and headaches. On the contrary, insufficient lumens hamper accurate color discernment. It slows reading speeds and decreases workplace accuracy. Lighting engineers calculate lumens to watts performance alongside reflectances, contrast ratios, and Unified Glare Rating (UGR) to circumvent such pitfalls. Higher-quality lighting solutions balance power efficiency and human-centric design for comfort and productivity.
Factors Influencing Lumen Requirement
- Size of the Office Space: For large offices, photometric simulations can inhibit uneven brightness at the periphery. Iterative reflective ceiling plan (RCP) modeling refines fixture spacing and beam spread for uniform illuminance across workstations.
- Purpose of the Lighting (General vs. Task-Specific): PCB inspection may demand 1000 lux or more. General areas can function at half that level. Compare lumens to watts to balance luminous flux against energy load and evade unwanted thermal buildup.
- Availability of Natural Light and Its Integration: High-performance glazing with spectrally selective coatings maximizes daylight without glare. Sensor-driven dimming maintains brightness to blend artificial sources with shifting sunlight.
Recommended Lumen Levels
Area/Task | Recommended Illuminance (lux) | Equivalent Lumens per Square Meter |
General Office Areas | 300-500 lux | 300-500 lm/m² |
Individual Workstations | 500-1000 lux | 500-1000 lm/m² |
Conference Rooms | 300-700 lux | 300-700 lm/m² |
Reception Areas and Lobbies | 100-200 lux | 100-200 lm/m² |
Task Lighting (Desk Lamps) | 450-1000 lux | 450-1000 lm/m² |
LEDIA Lighting Home Office Lighting Series
At LEDIA Lighting, we offer the LED Office Linear Light E series and the G Series linear pendant light, the best lighting for office with no windows. The fixtures have adjustable color temperatures and deliver upward and downward lighting for customizable ambiance.
Contact us for more information about our LED lighting solutions.