Do LED Bulbs Really Last 25,000 Hours?
The short answer: yes, but it's more complicated than the package claims. A 25,000-hour LED running 6 hours per day should last 11 years. But I've had LEDs die in 2 years and others still running at 7 years. The difference comes down to three factors: heat, dimmer compatibility, and manufacturing quality. Here's what I've learned from tracking LED lifespans across my house.
What Kills LED Bulbs Early?
Heat is the #1 killer. LEDs generate heat at the driver (the base of the bulb), not the light-emitting diode itself. If that heat can't dissipate — enclosed fixtures, recessed cans with no airflow, or upside-down installation — the driver overheats and fails. I had an LED die in 18 months in an enclosed porch light. The same bulb in an open fixture is still running 5 years later. Look for “enclosed fixture rated” on the package. Dimmer incompatibility is #2 — non-dimmable LEDs on dimmers die quickly. Cheap manufacturing is #3 — Feit and EcoSmart consistently fail earlier in my testing than Philips and Cree. My LED brand guide covers which brands last longest.
How Can You Tell an LED Is About to Fail?
LEDs don't burn out like incandescents — they gradually get dimmer. I measure brightness every 6 months with a $20 lux meter. A drop of 30% from the original output means the LED is near end of life. Other signs: flickering that wasn't there before, buzzing, or color shift (a 3000K LED that starts to look greenish). If you notice any of these, replace the bulb before it fails completely. Unlike incandescents, LED failure can sometimes involve the driver shorting — rare but worth replacing promptly.
When Is It Worth Replacing an LED vs Waiting for It to Die?
If an LED loses more than 30% brightness or starts flickering, replace it immediately. The energy savings from the new LED vs the dim old one will pay for the bulb within a year. A dim LED still uses about the same power as a new one — the efficiency doesn't improve as it ages. If the LED is 5+ years old and technology has improved significantly (higher CRI, better dimming), it's worth upgrading even if the old one still works. I replaced my 2019 LEDs with newer Philips Warm Glow models and the difference in dimming quality was dramatic.
References
- Energy.gov LED Lifespan Data — Official lifecycle and lumen depreciation data for LEDs.
- Rensselaer Polytechnic: LED Lifetime — Research on factors affecting LED lifespan.