Some people say that the higher the wattage, the brighter the fixture!
what affects the brightness of lamps the most is not the wattage, At first glance, this statement seems to be no problem. Indeed, wattage is one of the most important factors affecting the brightness of the lamp. But the premise is that in the case of “other conditions” are the same, the higher the wattage, the brighter the lamps.
Here, let’s talk about the “other conditions” here.
Speaking of luminance, we have to mention illuminance, and the two are a pair of easily confused concepts. Here we will briefly mention the difference between the two.
Brightness is more oriented to the human eye’s perception of light, while illuminance is the amount of light actually emitted from the fixture.
Illuminance is expressed in luminous flux (lux LX) in LM/㎡, i.e. lumens/m². The formula is: 1Lx = 1 Lm/㎡. In layman’s terms, it is the amount of light per unit area that the human eye can see. Assuming that the object is uniformly illuminated by light, then the luminous flux obtained on 1 m² is 1 lumen when it is 1 lux.
For example, we recommend that general activity lighting at home requires an illuminance of 100LX, or 100LM/㎡. While writing, reading, and other operational lighting require a higher illuminance of 300LX, which is 300LM/㎡.
Well, after a brief understanding of illuminance, luminous flux, lumens, and these optical terms, let’s talk about luminous efficiency, which is also an important factor affecting the brightness of the lamps.
The luminous efficacy value reflects the relationship between wattage and luminous flux (LX), that is, how many lumens (lm) of light each watt of light can bring, that is, Lm/W. The formula is luminous flux = wattage * luminous efficacy.
We take a 20W light bulb, for example, the luminous efficiency of 100lm / W, at this time, we say that the light bulb connected to a suitable power supply can produce the luminous flux: 20W * 100lm / W = 2000lm.
So since the wattage to judge the brightness has not met the demand, what should be used to judge it? The scientific basis for judgment is the lumen value.
So, what are the factors that affect the luminous efficiency of the lamps (bulbs)?
In fact, many factors influence, such as brand, technology, production process, packaging level, material, etc…
For example, A brand has a 7W LED bulb luminous efficiency of 80lm/W, and B brand has a W LED bulb luminous efficiency of lm/W, at this point, we will find that although the two can send the same brightness of light, B brand LED bulbs to be more energy efficient, because of high luminous efficiency.
Then again, different types of light sources are not comparable. For example, the light efficiency range of LED lights is usually between 90-160lm/W (some people say there are higher, we are just for the distance, not to seek proof), while the light efficiency range of energy-saving lamps(CFL) is usually between 40-90lm/w.
At this point, you take the same wattage of LED lights and energy-saving lamps to go brighter than the water, which is inherently unreasonable.
So judging the brightness of LED bulbs, wattage is only a reference value, need to look at its lumen value or luminous efficiency. Only when we can read the LED lamp packaging information, we can spend less money!
In summary, there are many factors that affect the brightness of LED lamps, as well as lampshade material, length of use, the color of the home environment itself, and so on. Therefore, we can not generalize that the higher the wattage, the brighter the fixtures. When we choose LED lights, pay more attention to more parameters on the good.