What we looked at
LED bulbs in open fittings
Zero failures in two years across eleven bulbs. This is the case the 25,000-hour rating describes.
RecommendedLED bulbs in enclosed fittings
Four failures out of six within twenty months. Heat has nowhere to go and the driver dies long before the diode. Buy bulbs explicitly rated for enclosed use.
Not recommendedLED bulbs on dimmer switches
Flicker and buzz unless both the bulb and the dimmer are specified for each other. Two failures out of five, and the surviving three flicker at low settings.
Recommended with reservationsFilament-style decorative LEDs
Pleasant light, shortest lives in our test. The form factor leaves almost no room for heat management.
Recommended with reservationsWe have been replacing bulbs in the same house for two years and writing down what failed. Twenty-two bulbs, four brands, a mix of fittings.
The rated life on every box was 15,000 to 25,000 hours. At three hours a day that is fourteen to twenty-three years.
We have had six failures.
Where they failed
| Fitting type | Bulbs | Failures | Failure rate |
|---|---|---|---|
| Open pendant or shade | 11 | 0 | 0% |
| Fully enclosed | 6 | 4 | 67% |
| On a dimmer | 5 | 2 | 40% |
Nothing failed in an open fitting. Two thirds of the enclosed ones did.
Why enclosure is the variable
An LED bulb is a diode plus a small power supply — the driver — packed into the base. The diode lasts approximately forever at domestic power levels. The driver is electronics, and electronics degrade with heat.
In an open fitting, the heat leaves. In a sealed glass fixture, it does not, and the driver sits in an oven for three hours a night for a year and a half.
So the bulb does not usually fail because the light-emitting part wore out. It fails because the power supply cooked — and the 25,000-hour figure on the box describes the diode under laboratory cooling, not the driver in your bathroom.
Some manufacturers now print “suitable for enclosed fixtures” on the packaging. Those are the ones to buy for those fittings, and they cost slightly more for what is essentially better thermal design.
Dimmers are a compatibility problem, not a quality one
Two of five dimmer bulbs failed and the three survivors flicker at low settings.
The cause is that most domestic dimmers were designed for incandescent loads and work by chopping the mains waveform. An LED driver receiving a chopped waveform behaves unpredictably, and “dimmable LED” only means the bulb tolerates some dimmers.
If you have LEDs on a dimmer and they buzz or flicker, the bulb is usually not faulty. The pairing is wrong, and replacing the dimmer with a trailing-edge type designed for LED loads fixes more cases than replacing bulbs does.
The decorative ones
Filament-style LEDs — the ones imitating a vintage bulb — had the shortest lives in our test.
The form factor is the reason. A slender glass envelope with visible filament strips leaves almost nowhere to put a driver and no thermal mass to spread heat into. They look lovely and they are working against physics.
What we do now
Open fittings: buy on price, any brand, they all last.
Enclosed fittings: buy bulbs explicitly rated for enclosed use, and accept paying a little more.
Dimmers: fix the dimmer, not the bulb.
And keep one spare of each type in a drawer, because the failures come in clusters — bulbs bought at the same time and installed in the same fitting fail within weeks of each other, which makes sense once you accept that heat is what killed them.
Martin Halvorsen
Contributing writer, Household
Writes about the objects in a home and how long they last. Buys everything he writes about.
Elsewhere in the magazine
- Food storage containers: we used six sets for eighteen months and the lids decided everything
- Chef's knives: I cooked with five for a year and the £30 one is still the one I reach for
- Nonstick pans: I bought five and cooked eggs in them for two years. Price predicted nothing.
- Vacuum flasks: we filled six with boiling water and left them overnight. The £15 one lost 4°C more than the £45 one.