If you’re new to the lighting industry, or if you're a business owner looking for energy efficient lighting solutions, you may have come across some terms that might not be entirely familiar. In a previous blog, we discussed color rendering index, color temperature, and foot-candle.
Luminous efficacy is a measurement commonly used in the lighting industry that indicates the ability of a light source to emit visible light using a given amount of power. It is a ratio of the visible energy emitted to the power that goes into the bulb from the electrical line (visible energy emitted is also known as luminous flux, and the units are measured in lumens). Note: in some countries, luminous efficiency is substituted for luminous efficacy. Luminous efficiency, however, is a unitless measure (watts out / watts in) where luminous efficacy is not (lumens out / watts in).
This begs an obvious question...
What’s a lumen?
A lumen (lm) is the total amount of light emitted by a light source. It’s a unit of luminous power. 1 lumen = 1 candela (luminous power per unit solid angle) x 1 steradian (unit solid angle)
You’ll most likely see lumens (lm) or luminous efficacy (lm/watt) on your light packaging. In the meantime, here’s a great graphic from the Oregonian:
Notice how it takes less power (watts, W) to get the same lumen output as you move from standard incandescent lights to halogen bulbs, CFLs, and then eventually LED lights. If you were to look at the first row and divide the 450 lumens figure by the different wattage required to produce it, you would get the luminous efficacy (11.25 lm/W for incandescent, 15.51 lm/W for halogen, 45 lm/W for CFLs, and 90 lm/W for LEDs). What this means is that LED technology is beating traditional incandescent light bulbs by nearly a whole order of magnitude (5 to 8 times as efficient depending on the desired brightness). Interestingly enough, as you move from left to right along the chart, the lifespan of the light source also begins to drastically improve. LED lights typically last 10 to 20 times as long (15-25 years) as an incandescent bulb (1-2 years). They also last nearly twice as long as the next best alternative (CFLs last approximately 10 years).
So what does this mean for energy efficient lighting solutions? The answer is simple...utilize LED technology in your municipality, real estate organization, educational facility, hospital, or other structure. Not only do LED lights offer better luminous efficacy, but they will also last longer (which can cut down on maintenance and replacement costs). Of course, implementation and finding the right solution for your facility or business takes a little industry expertise. At Stouch Lighting, we would be happy to schedule a 20-minute, no-obligation phone call to help you assess your lighting and energy management needs. Contact us today!