Light emitting diodes (aka LEDs) are far better choice for lighting your home than metal halide or traditional fluorescent lights. Compared to them, LEDs last 8-10 times longer and utilizes 70%-80% less energy.
In short, replacing conventional light bulbs with LEDs can save you a lot of money in the long run.
However, no light bulb lasts forever. Aging in LED bulbs is measured through lumen depreciation. If you’ve never heard this term before, don’t worry, we’ll lay out all the details.
Lumen Depreciation Simplified
As said above, LEDs have a considerably longer lifespan in comparison to metal halide or fluorescent lights. All the same, LED bulbs too age and need to be replaced at some point or another. However, unlike conventional bulbs, LEDs don’t become dead as a dodo all of a sudden. Instead, they start emitting fewer and fewer lumens as they age.
Lumens refer to how much light you’re getting from a light bulb. More lumens = Brighter light.
When you install an LED light bulb, it produces initial lumens, defined as the total amount of light emitted by a light source just after it’s stabilized but before deprecation has set in.
In simplest language, a new LED bulb is at its brightest. Over time, its output reduces — though this is a very gradual process, mind you. This reduction in lumen output is what is referred as “lumen depreciation.”
To calculate lumen depreciation of an LED bulb, divide its lumen output at any particular point — referred as mean lumens — by its initial lumen output. The result will be a decimal. So if the lumen depreciation is 0.75, it means the LED bulb is working at 75% of its original capacity.
So, at what point should you replace an LED bulb?
While opinions differ to some extent, most experts believe the right time to replace an LED bulb is when its lumen output drops to 70%.
Defined in hours, the lifetime of an LED bulb is defined as the time it takes till its light output reaches 70% of its initial output. This is also called L70.
LEDs, in general, have a life expectancy of 50,000 hours. In other words, if you use your lights for 10 hrs every day, your LED bulbs will last for 13.7 years!