Lumens versus Wattage

Lumens and wattage are both units of measurement for different properties of light.

Wattage refers to the amount of power used by a light source to produce light. It is a measure of the energy consumed by the light source, not the amount of light it produces. In other words, wattage measures how much electricity a light bulb uses, not how bright it is.

Lumens, on the other hand, refer to the amount of visible light that is emitted by a light source. It is a measure of the brightness of the light, rather than the amount of energy used to produce it. Lumens are a more accurate measurement of the actual amount of light produced by a bulb, as they take into account the sensitivity of the human eye to different wavelengths of light.

In the past, people used to equate wattage with brightness, assuming that a higher wattage bulb would always be brighter. However, with the development of energy-efficient lighting technology, this is no longer the case. For example, a 100-watt underwater light with a “low wattage” can produce the same amount, or more light than a traditional 175-watt mercury vapor or 150-watt metal halide lamp both with a higher wattage. This is due to the fact LED’s are capable of much higher lumens-per-watt than older HID lamp technologies.

When researching underwater lights, make sure the math makes sense. Be cautious of extraordinary claims of “30,000 lumens” from 80w-100w power supplies putting calculated LED efficiencies at unrealistic claims of 300-375 lumens per watt. Big Water Lights power supplies list output power, voltage, and current. Together with provided lumen ratings, one can validate the total system with realistic LED emitters.

In summary, wattage measures the energy consumed by a light source, while lumens measure the amount of visible light emitted by a light source. When choosing a light bulb, it is important to consider both wattage and lumens to ensure that you get the brightness you need while minimizing energy consumption. When in doubt about how bright an underwater light kit may be, make sure the lumen math is realistic before you make your purchase.