FAQ - LED Life Expectancy

According to the claims from various manufacturers LED lighting has a life expectancy of 20,000 to 50,000 hours. At 8 hours per day this would be approximately 17 years. This is roughly 30 times longer than incandescent bulbs and 5 times longer than compact fluorescents. This estimate from the manufacturers is in fact more of a guess-estimate based on accelerated wear testing, which isn't a precise science and is only conducted at the component level; rather than at the system/luminaire level. In some cases we suspect claims of 50,000 are just wishful thinking (especially from the cheaper vendors), but as these high powered LED lights haven't been in the market for 20 years as yet, it is hard to disprove or prove any claims. There are several factors that can shorten (often dramatically) the life of a LED globe.

Heat. LED lights normally have metal heatsinks to draw the heat away from the LED chip itself. If the heat sink is not adequate in size, poorly connected or of a poor design the LED can overheat and fail very rapidly. The same applies to degradation of the driver electronics.

Poor Electronics. Incandescent lights are simple, they are basically just a thin metal filament. LEDs are more complex. Capacitors and other components are normally required as part of the power supply regulation and conversion of AC current into the low voltage DC current required by the LED. While the LED itself might have a life span of more than 10 years, other components might not. Electrolytic capacitors in the ballast of LED luminaires are a known limiting factor of a luminaires lifetime due to their low tolerance for elevated temperatures. These components can be internal or external to the LED depending on the light.

Fitting type. LED retrofit designs with bayonet, edison, gu10 and mr16 fittings are all designed for AC supplies. This requires a greater amount of electronics housed within a compact, heat-sensitive product. The volume constraints of these designs can limit optimal component selection and thermal management and render it unserviceable in the event of failure. LED kits with external drivers have the advantage of generally better thermal management and isolating the most likely source of electronic failure to the driver unit, rendering servicing simpler and cheaper.

Environmental factors. Higher than expected ambient temperatures in a roof space, lack of airflow around the heat sink or poorly regulated mains power supply can be detrimental to the life of a LED. Too much heat is probably the #1 killer of LED lights.

There are also two additional factors that might lead you to wanting to replace your globes before they actually fail.

Decreasing output. A further issue is that the light output of a LED light can decrease slightly over time. Sometimes this is quoted as a L70 or L50 figure, meaning that the light will keep 70% (or 50%) of it's original output during it's quoted lifetime. (Decreased output can happen with other forms of lighting as well, so it isn't a problem unique to LEDs). There also could be other issues like the plastic lens cover becoming cloudy over time decreasing light output.

Better technology. 10 years from now, you can be sure that LED efficiency and light quality would have improved beyond what is possible today. So you may find that 10 years down the road you'll want to replace your existing globes even if they haven't failed.

Some example lifetimes

Note that the typical claimed maximum LED operating temperature, of around 45°C, is below record temperatures for all Australian states (except Tasmania). Therefore it is possible for the ambient temperature to exceed the operating temperatures of these lights. This is without considering how much hotter the roof space might be for downlights.

The 20,000 - 50,000 hour lifespan quoted in manufacturer specifications is based only on projected lumen depreciation of the LED chip and does not factor in the other possible modes of failure, which could occur earlier. These figures therefore give no indication of a product's overall reliability, which is still best gauged from the manufacturer's warranty period.