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Effects Of Temperature On LED Lights

Believe it or not, air conditioning can make your lights brighter, though not directly, of course, and only as it pertains to LED lights.

Why?

“In general, the cooler the environment, the higher an LED’s light output will be. Higher temperatures generally reduce light output. In warmer environments and at higher currents, the temperature of the semiconducting element increases,” according to the National Lighting Product Information Program.

What Does Heat Do To LED Light Strings

Temperature has a tangible effect on the material and output of an LED light. If you take anything from this article, just remember these two things when it comes to the performance of LED lighting in various temperatures:

Heat is bad. Cold is good.

LED lights will function at 100 percent output with a junction temperature — or the temperature inside the bulb at the source where electrical energy passes through — of 77 degrees Fahrenheit, according to the same source. As the temperature increases to around 120 degrees Fahrenheit, light output diminishes to about 90 percent, which is considerable but not necessarily noticeable. At around 185 degrees Fahrenheit, the junction will fail. Depending on where you’re located, careful selection of outdoor lighting sets may be prudent.

Ambient temperature — or the temperature of the air in the environment the bulb is in — will directly affect junction temperature, which altogether is a function of ambient temperature, the electrical current, and the amount of heat sinking material in the LED. A heat sink is normally a material in or around the source of heat, often being something like metal that will cool through conduction, pulling heat away from the sensitive LED materials.

In other words: keep things cool around the bulbs when possible. It’ll improve their output. 

Though, if it’s too cool, the light may overperform. Below 77 degrees Fahrenheit junction temperature, it may exceed its normal light output. LEDs are semiconductor light sources. The electric current that flows through them is unlike incandescent bulbs, which have to heat up to a certain temperature in order to emit light. A CFL light, similarly, may fail to start in cold temperatures. 

Effects of Hot vs Cold On LED Lights

LED lights use an electronic driver, not a combustible source.

The low thermal stress of a cold environment places less of a strain on the diodes and driver, writes Mikael Shams.

“In fact, studies show that when installed in cold applications, LEDs’ rate of degradation reduces and their lumen output improves,” Shams said.

Continuing with that thought, in a hot, humid environment, an LED light could potentially have a lower lifespan. 

“Prolonged heat can significantly shorten the useful life of many LED systems. Higher ambient temperature leads to higher junction temperatures, which can increase the degradation rate of the LED junction element, possibly causing the light output of an LED to irreversibly decrease over the long term at a faster rate than at lower temperatures,” according to the National Lighting Product Information Program.

To steal an analogy from LED expert Victor Adrian Floroiu, LED lights are like tires. Tires will still function as their tread wears down over time. However, a car doesn’t break as effectively or grip the road as readily with worn down tires.

The same thing goes for LED lights. The technical term for this is called “lumen depreciation” and it’s a measurement of how much lower the light output is in LED lights over a span of time. Once light output is at 70 percent of the initial value, an LED bulb is generally replaced. This 70-percent value is actually an industry standard acronym — L70. 

The previously mentioned 77 degrees Fahrenheit is the most commonly used temperature to gauge a bulb’s L70 lifespan.

Constant exposure to high heat can exacerbate lumen depreciation and therefore lower the amount of time an LED light is rated for. Most experts generally agree that heat is the biggest threat to LED lights.

Conversely, because cold ambient temperatures keep the diodes and driver cool, the life of an LED light will actually be extended. 

Those in cold environments should therefore doubly consider LED lighting solutions on top of all the longstanding and proven benefits. While those in hot environments should think long and hard about managing the heat of their building, structure, or organization — if not for the good of the people within it, which should be reason enough, then for the economic outcomes of a proper LED lighting system.