I listen to NPR during the weekdays in my car because they often have wonderful learning information that has nothing to do with their left bias in politics…..which I also see as learning why the left thinks the way it,they do with professionals providing an eloquent case much of the time…..even when I disagree.
Anyway, they devoted a segment to understanding the terms in the title that was very enLIGHTning that I’ll share later, after leaving Subway and going to the gym.
https://www.any-lamp.com/lumen-to-watt
Lumen is the term used to describe the total amount of light emitted by a light source, while wattage merely indicates the amount of energy it uses. As lighting becomes more and more energy-efficient, the same number of lumens is being achieved with lower and lower wattages. That's why, when you replace an incandescent bulb with an LED one, for instance, you should compare the number of lumens rather than the wattage to ensure the brightness is the same. The table below clearly shows the number of lumens that are generated by different types of bulbs at various wattages.
Type of bulb | 200-300 lumens | 300-500 lumens | 500-700 lumens | 700-1000 lumens | 1000-1250 lumens | 1250-2000 lumens |
Incandescent | 25-30 watts | 40 watts | 60 watts | 75 watts | 120 watts | 150-250 watts |
Halogen | 18-25 watts | 35 watts | 50 watts | 65 watts | 100 watts | 125 watts |
CFL | 5-6 watts | 8 watts | 11 watts | 15 watts | 20 watts | 20-33 watts |
LED | 2-4 watts | 3-5 watts | 5-7 watts | 8-10 watts | 10-13 watts | 13-20 watts |
A foot-candle is how bright a light is one-foot away from its source. Lighting requirements/needs vary depending on the type of room being lit. For example, a bathroom or kitchen will require more foot-candles than a living room or bedroom.
Kelvin Color Temperature Scale for Light Fixtures
2000K-3000K: Gives off a warm white/yellow glow (candlelight hues)
3100K-4500K: Gives off a bright, cool white glow
4600K-6500K: Gives off a crisp daylight glow (white/bluish hue
What is color temperature?
Color temperature, is defined as “the temperature of an ideal black-body radiator that radiates light of a color comparable to that of the light source.” (Wikipedia) A blackbody is an object that absorbs all radiation, which includes visible light, infrared light, ultraviolet light, etc.
In laymens terms, color temperature is used as a method of describing the warmth or coolness color characteristics of a light source.
Color temperature, in practice, is only useful for light sources that fall in a color spectrum of reddish/orange (yellow based) to white (blue based). This is because this spectrum corresponds closely to the radiation of a black body, whereas purples and greens do not.
This range of color can be seen when heating metal, which initially emits red light that graduates from orange to yellow, then from white to blue.
The spectrum of color temperatures is assigned numerical values, measured in degrees of Kelvin. And these values are used to describe the color emitted from fixtures when working with lighting.