how long do led lights last

Nowadays, LED lights have become the mainstay of lighting. Compared with traditional lighting, they have many advantages, such as higher energy efficiency, longer lifespan, eco-friendliness, and smart control features.
But how long do LED lights really last? What factors affect their lifespan? How can extend lifespan of lights? This chapter explains the two major areas of home and industrial LED lighting.

2. Theoretical Life Of LED Lights

The theoretical life of LED lights usually refers to the time it takes for the light to decay to 70% of the initial brightness (L70 standard), industrial grade can reach the L90 (light decay 10%) standard, but the actual life is significantly affected by heat dissipation, power quality, and operating environment.

2.1 Specific explanation of light decay and Last Long

In fact, the light decay of any LED starts from the first day, that is, the brightness will dim over time, but the speed is very slow in the early stage.

StandardMeaning
L70The time when the luminous flux drops to 70% (commonly used in general lighting)
L80The time when the luminous flux drops to 80% (commonly used in high-end lighting)
L90The time it takes for the light to decay to 90%, and the light quality is still very high (used in medical and museums)
B5050% of the lamps have a light decay value that reaches the target value (e.g. L70)

If the nominal life of an LED light is 50,000 hours (L70), it means:

Under normal use and appropriate heat dissipation conditions, its brightness after 50,000 hours is about 70% of the factory brightness. At this time, it can still be used, but the brightness has begun to decrease significantly.

Common Misconceptions : It does not mean that the lamp will completely burn out or not light up after 50,000 hours. It also does not mean that the light will start to decay after 50,000 hours.

2.2 Theoretical LED Light Longevity Industry Standard

*The lifespan is the data given by the manufacturer and is for reference only. *The service years is a theoretical conversion and the actual time will be affected by various factors.
Type Theoretical Life (Hours) Continuous Use Years Recommended Applications
Home LED 15,000 – 25,000 hours 5 – 8 years(8 hours per day) bedroom, kitchen, living room
Industrial LED 50,000 – 100,000 hours 14 – 28 years(10 hours per day) factories, warehouses, tunnels, ports, stadiums, parking lots, etc.

2.3 Why Industrial LEDs Last Longer?

The industrial led last longer is because its materials, hardware, and chips are better, and it has undergone rigorous testing, and its price will be much more expensive than home LED.
Lifespan Factor Residential LED Industrial LED
Heat Dissipation Design Basic aluminum or plastic casing, passive cooling Die-cast aluminum + fin structure / active fan cooling, high thermal conductivity
Driver Quality Basic constant current driver, 80%~85% efficiency Wide voltage industrial-grade driver (100–277V), >90% efficiency, surge protection
LED Chip Quality Mid-tier chips (e.g. 2835/3030) High-efficiency COB or flip-chip (e.g. Lumileds, CREE)
Protection Rating IP20 ~ IP40 (dust protection only) IP65/IP66 (waterproof and dustproof), vibration & corrosion resistant
Operating Temperature -20°C – +40°C -50°C – +75°C, suitable for harsh environments

3. How Is LED Last Long Calculated?

The longevity of LED is not calculated by simple mathematical formula, but is based on the comprehensive results of accelerated aging experiments + mathematical model deduction. The core goal is to predict the degree of light decay (such as L70/L80/L90 standards).

3.1 LM-80 Test (luminous decay experiment of lights)

Test object: Only for LED chips/light modules (excluding power driver)

Conditions: Under constant current drive, place the LED in three temperature environments: 55℃/85℃/105℃.Continuously light up for 6,000 hours (about 250 days), and measure the luminous flux every 1,000 hours

Output: Generate a light decay curve (temperature vs. brightness decay rate)

3.2 Why is actual lifespan much lower than theoretical?

  • Power supply short board effect
    The life of the driving power supply is usually only 10,000 to 30,000 hours (electrolytic capacitors dry up, MOS tubes burn out), while the theoretical life of the lamp beads exceeds 50,000 hours.
  • Industry consensus: The life of the whole light = min(light bead life, power supply life)
  • Heat dissipation design defects
    Poor quality heat sinks cause the junction temperature (Tj) to soar: for example, in a nominal 25℃ environment, the actual Tj can reach 120℃ (far exceeding the chip temperature resistance of 85℃).
  • Nonlinear deterioration of the light decay curve
    The initial light decay is slow (<3% in the first 2,000 hours), and it accelerates in the later stage (such as annual decay >10% after 50,000 hours).

3.3 Industry Truth:

LED street lights claiming to have a “100,000-hour lifespan” are actually tendered for municipal projects based on an L80 lifespan of ≥60,000 hours (approximately 7 years).

The lifespan of household LED lights is marked as 25,000 hours, but due to reduced power supply, the actual average failure time is 8,000~15,000 hours (data source: CNAS laboratory sampling).

In actual use, power supply and heat dissipation are the main factors affecting the lifespan. When purchasing, you should pay close attention to the heat dissipation design and power quality, and don’t be superstitious about the “100,000 hours” propaganda.

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