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Lumen Output: Why Wattage Is a Thing Of The Past

Posted on October 1, 2020 by Hugh Kollosche
When you go to buy compact fluorescent or LED light bulbs today, you might wonder why they are marketed according to the amount of “lumen output” they provide. You may be more familiar with the wattage rating traditionally associated with incandescent light bulbs. However, the lumen rating of a bulb is a more accurate indicator of how much light it is able to provide than its wattage rating. The use of wattage as an indication of light output worked for incandescent light bulbs because it was a simple equation where electrical current flowed through a filament and the thickness and number of coils in the filament dictated how much power it consumed and how much light was emitted. With compact fluorescent and LED light bulbs there are many more variables and therefore each form of light bulb must be tested for its lumen output. lumens and wattage Below is a detailed discussion on both lumens and wattage ratings of LEDs and the how to choose between the two:


A bulb’s wattage tells you the amount of electricity it consumes. This helps homeowners who are conscious of their daily energy use. The wattage rating can also tell you which fixtures they are suited for. High-wattage bulbs can be a fire hazard due to the amount of heat generated if it is installed in the wrong fixture. 


Lumens are the measurement of a bulb’s illumination levels. The lumen output can be represented in two ways: the total lumen output for example 800LM or as a percentage of the total wattage of the light bulb, for example the lumen output for a 8 watt light bulb could be represented as 100LM per Watt (8 x 100 = 800LM total).  It’s easy to mistake a bulb’s wattage rating to be the amount of light it can produce. This is why people are often surprised by the rate of lumen a high-wattage bulb provides. Typically, a Compact fluorescent or LED light bulb is more efficient then the traditional incandescent light bulbs we have been used to, therefore the new technology light bulbs have higher lumen production rating. As touched on earlier, it has become necessary to measure light output in lumen because both compact fluorescent and LED light bulbs use solid state electrical components in the process to produce light. As the quality of solid state components can vary from manufacturer to manufacturer the choice of components used can have an effect on the light output, for example a 10 watt LED bulb from one supplier might produce 100LM per watt, but a similar 10 watt LED bulb from another supplier may only produce 85LM per watt. This illustrates very clearly why we can no longer use wattage as a measure of light output.

Taking advantage of a bulb’s lumen rating

The reason why many people are now choosing their bulbs based on their lumen rating is for specific lighting purposes. For example, some might choose a bulb with a low lumen rating of 20-50LM per square metre to provide lighting for corridors, for kitchens and home offices 250-300LM per square metre and for home living areas 100-150LM per square metre. By picking a light bulb based on its lumen rating, you can provide enough brightness within a room or area without consuming more electrical energy then necessary. Apart from prioritising lumens, it is also important to buy quality light bulbs or globes from a respected store, such as Discount Lighting. Browse through our large range of lighting products through our online store today and find the perfect lighting solution for your home.