As the occurrence of kinds of energy-saving bulbs and as a lot of people are becoming more and more familiar with the lumen knowledge, recently, all the countries are keep emphasizing that lumen is the standard when buying a bulb. That will probably change a lot of customers’ established habit or attitude that buying bulbs based on the watt.
How can we tell the difference between lumen and watt?
Put it in a easiest way, Watt = how much power a bulb uses: Lumen = how much light it gives/outputs.
A bulb is simply a device that converts watts (electricity) into lumens (light). The unit of input power is watt, can use it to evaluate the energy consumption, and it related to your electricity per month. If the watt is higher that is to say, you will consume more energy. However, the unit of luminous flux (the total visible light that bulb gives) is lumen, can use it to evaluate the brightness. The higher the lumen, the brighter the bulb.
If two bulbs got the same watt, that means the will consume the same amount of energy, but the lumen might not be the same. For example, the luminous flux of a 40w incandescent bulb is 350lm, but for a 40w fluorescent tube, the luminous flux is 2100lm. They consumed the same amount of energy but the fluorescent tube is much brighter.
How to convert watts to lumens?
Because lighting effect= lumen/watt, so if you want to turn the watt to lumen, you can try this one: Watt*lighting effect=lumen
For example the lighting effect of LED factory light form Lighting Ever can be 100lm/w, so the Luminous Flux of this light is 10000lm.
The lighting effect of LED factory light from some normal brands can only be 70-80lm/w, so the Luminous Flux of this light is just 7000-8000lm, much lower than l0000lm, but consumed the same amount of energy.
We cannot choose the energy-saving bulbs according to the old wattage standard anymore. Lumen and lighting effect are the most important factors when choosing a bulb now. The following tables are a rough comparison of LED bulb’s lumen and traditional incandescent bulb’s watt.
How to regard watt and lumen when buying a bulb?
If we just want to buy some incandescent bulbs, it’s ok to use watt as a choosing standard. But if we keep using incandescent bulbs, it’s easy to cause over-illumination in a lot of places let alone saving energy. And the energy-saving bulbs (Halogen/CFL/LED) can give out the same brightness but consume less energy. That is to say, if incandescent bulbs and energy-saving bulbs got the same power (wattage), the energy-saving bulbs will be much brighter. So a lot of people are start thinking about lumen rather than wattage when buying a bulb.
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