LEDs don’t fail suddenly — they slowly lose brightness over time. Manufacturers state lifetime using Lx, By and Cz values (for example L70 B20 C5). Typical rated lifetimes today are often between 70,000 and 100,000 hours.
This article explains those values in plain language, lists the main environmental factors that shorten lifetime, and gives practical, non-technical tips for users and buyers.
LED fixtures are known for long life, but many users notice lower brightness after several years. Instead of measuring a single “hours to failure,” manufacturers specify how much light remains after a certain runtime.
Understanding this helps you choose the right product, install it correctly, and plan simple maintenance.
For LEDs, lifetime is usually not the moment the lamp stops working. It refers to the reduction of light output over time.
Manufacturers often specify rated lifetimes like:
These values are typically provided together with L/B/C values. They help you plan replacement cycles and set realistic expectations.
Further reading: https://sensorasmart.com/
In short:
Lx – Remaining light as a percentage after the stated hours
Example: L70 = 70% of initial light output remains.
By – Share of luminaires below the Lx threshold
Example: B20 = 20% fall below that level.
Cz – Share of luminaires that have completely failed
Example: C5 = 5% total failure.
“L70 B20 C5 at 70,000 h” means:
These figures are useful for planning replacements and understanding long-term light quality.
This information is relevant for:
It helps buyers make informed decisions without needing deep technical knowledge.
The real lifetime of an LED depends heavily on its environment. Key factors include:
High temperature
Heat is the most common enemy. Excessive fixture temperature shortens chip and electronics life.
Moisture and condensation
Damp spaces and temperature swings can corrode contacts or damage electronics.
Salt or chemical exposure
Coastal locations or chemically aggressive environments increase corrosion risk.
Dust and dirt
Dirty optics reduce light output and can create local overheating.
Electrical quality
Voltage spikes, unstable supply, or low-quality drivers increase failure risk.
Mechanical stress
Vibrations or repeated shocks can loosen connections.
If you know the installation environment, you can select appropriate IP protection, materials, and driver quality.
You don’t need to be an engineer to help LEDs last longer. Consider these practical steps:
Small measures can significantly improve lifespan.
Rarely. Most LEDs gradually lose brightness over time. Individual electronic failures can occur, especially with poor power quality or low-quality drivers.
Ask for:
Understanding Lx/By/Cz values and environmental influences helps you avoid surprises and make smarter purchasing decisions.
If you’d like, send a datasheet or describe your intended installation. I can help interpret the values and provide a short, practical recommendation tailored to your situation.
Further information: https://sensorasmart.com/
Book a meeting with Dan Flühmann: https://meetings-eu1.hubspot.com/daniel-fluehmann