Light Output: Lumens vs. Watts
by Bruce W. Smith
Some manufacturers lead buyers to believe there’re only two terms that matters when it comes to the quality of aftermarket lights: watts and candlepower.
Both are very misleading.
Watts is only a measurement of current draw (Volts x Amps= Watts); it’s the automotive equivalent of how many gallons of fuel-per-hour an engine uses – not the miles-per-gallon the engine in the pickup delivers driving down the road.
For example, a 100-watt HID driving light is far more effective lighting up the road than a single 100-watt light bulb sitting on the bumper.
The difference is in how the bulb’s light output is focused, which brings up another misleading marketing term: candlepower or candela.
Candlepower (aka candela) is an antiquated measurement of light output at the source (radiance) and has nothing to do with how that light illuminates an object.
Lumens, on the other hand, is a true measurement of a light’s efficiency at lighting up an object at a specified distance.