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Most people are used to thinking of brightness in terms of watts. A 40-watt bulb is less bright than a 60-watt bulb. The watt has been an easy way to think about brightness and power because the wattage correlates to the brightness while also hinting at the power draw a giving bulb will have and, therefore, how much it will cost to run that bulb.

LEDs can produce better, brighter light using fewer watts. Often LEDs have “wattage equivalents” printed on their packaging so that the customer can approximate the kind of LED bulb needed without having to learn a whole new set of reference points. However, in many cases the wattage equivalent simply isn’t good enough. Lumens are on their way to replacing watts as the new standard unit of brightness.

A lumen is a measure of the total quantity of visible light emitted by a source per unit of time. It’s similar to a watt in that it is a measure of light over time, but it differs from a watt in that a watt is a way to quantify the amount of energy consumed over a period of time, which can point to brightness, but is an indirect way to measure it.

For a quick guide do more lighting-related terms, check out our glossary here.

A 60-watt incandescent bulb loses 95% of the energy it consumes to heat, meaning only 3 watts of energy are being turned into light. A Sunlake 60-watt equivalent bulb consumes an average of 9 watts, producing 800 lumens of crisp, clean, high-quality light. Far more lumens than a traditional incandescent bulb.

That’s a good background for getting better light with fewer watts, but how can you get better light with fewer lumens? This has to do with a number of factors. Whereas traditional lights are omni-directional, meaning they require mirrors to focus the light they create, LEDs are directional. The LED chips can be placed in precisely the right locations to direct the light to the optimal location without using mirrors. Every bounce cuts down on the luminosity as some light particles are absorbed by the surfaces they encounter.

CRI is an important factor in this as well. You need fewer lumens when you have higher lumen quality. 60,000 lumens from a High-Pressure Sodium light will often appear less bright than an LED lamp producing 20,000 lumens. Lower CRI means items appear less clear, and less accurately rendered than they would in standard daylight. High quality LED light can produce light with exceptionally high CRI ratings, thereby making it appear brighter.

There are actually two different types of lumens: photopic and scotopic. Photopic lumens relate to how a camera perceives light and are measured by a light meter. Scotopic lumens are what humans use to see. A light meter can pick up wavelengths of light beyond just the visible spectrum. When lumens from a traditional incandescent light are picked up by a light meter and converted to scotopic lumens, it’s possible they’re being inflated by the UV and infrared light the light meter can also detect. LED light typically only produces light in the visible spectrum. Therefore any lumens picked up by a light meter and converted to scotopic lumens are a purer value of lumens for the purposes of human vision.

It all comes down to a matter of perception. LEDs produce better-quality, less expensive light than their traditional counterparts. Lumen degradation, light absorption, and inefficient incandescents, all lead to wasted energy and lost light quality. For superior light for less money, LEDs are your best bet.