The box gives a bulb’s life in years, based on 3 hours a day, and many list its rated hours too. For an LED those hours mark when its light is expected to have faded to 70% of new, because LEDs dim slowly instead of burning out.
Hours and years on the box
The years on the Lighting Facts label are worked out at 3 hours of use a day. To turn a rating in hours into the same years, divide it by 1,095, which is 3 hours times 365 days.
| Bulb | Type | Hours | Years at 3 a day |
|---|---|---|---|
| OM60DM/927CA/4, A19, 8.8 W | LED | 25,000 | 22.8 |
| BPESL13T/GU24, twist, 13 W | CFL | 10,000 | 9.1 |
| 40A15/CL/2/HDRP, A15, 40 W | Incandescent | 2,000 | 1.8 |
| BPQ25/G9/RP, G9, 25 W | Halogen | 2,000 | 1.8 |
| T48/840/LED/2, 4 ft. tube, 14 W | LED | 50,000 | 45.7 |
From Feit’s product pages. Ratings differ from bulb to bulb, so read the box of the one you have.
What the hours mean for an LED
LEDs typically don’t fail all at once. Their light dims a little at a time, and an LED’s rated life is the point where its output is predicted to be 30 percent lower. So a 25,000 hour LED is rated to still give 70% of its first light at 25,000 hours. This is often written L70.
The FTC’s labeling rule defines a lamp’s life as the hours until half of a large group of them has failed. An incandescent bulb usually goes when its filament wears out, and the metal that wears off the filament is what leaves an old bulb’s glass looking dark.
If the light stays on all day
A light that never goes off runs 8,760 hours a year. At that pace a 25,000 hour rating lasts just under 3 years, and a 2,000 hour incandescent about 12 weeks.
What does it cost to leave on?
Cost to leave a light onHeat wears an LED out sooner
An LED’s life depends most on how well it gets rid of its heat. Inside a closed glass fixture, choose an LED rated for enclosed fixtures, such as Feit’s OM60DM/927CA/4. GE warns that one without that rating may lose life and light there. See LEDs in enclosed fixtures.
CFLs and switching
Feit says a CFL’s life drops significantly when it’s switched on and off often.