25,000 hours — what does that mean in daily work?

The LED rings in our magnifying lamps are rated at around 25,000 operating hours. That figure appears in every datasheet and means little to most people. Translated into working time it becomes tangible:

For the vast majority of users that simply means: the LED outlives the lamp. What gives up sooner in practice is the mechanics — a worn joint, a chafed cable — or the power supply.

LEDs do not burn out, they fade

That is the difference from the incandescent bulb and the fluorescent tube, and it is often misunderstood. An LED has no component that suddenly breaks. It slowly loses brightness over its operating time.

The figure of 25,000 hours therefore does not describe failure but the point at which a defined share of the original brightness remains — 70 per cent is the industry norm. The lamp keeps working afterwards, just more dimly.

In practice you hardly notice, because it happens so gradually: the eye adapts along with it. It usually only becomes obvious when a new lamp stands next to it.

What shortens service life

The most important factor is heat. LEDs age faster the hotter they get in operation. Two things help against that, and both cost nothing:

• Keep ventilation openings clear. Do not lay cloths over the lamp head, do not press it tight against a wall or into a niche.
• Do not run permanently at full power if you have a dimmable lamp and less is enough. That spares the LED and your eyes alike.

Frequent switching on and off, by contrast, does not harm an LED — unlike a fluorescent tube, where every strike stresses the electrodes. You may switch the lamp off at lunchtime without hesitation.

What running it costs

A magnifying lamp draws between 10 and 12 watts depending on series. Calculated for a full-time workplace with around 2,000 operating hours a year and an assumed electricity price of €0.35 per kilowatt-hour:

The difference is therefore about seven euros a year — and the LED lamp delivers the higher luminous flux at that. Anyone switching from tube to LED purely because of electricity costs will not recover it within a year; anyone facing a new purchase anyway gets the advantage on top of all the others.

Recalculate with your own electricity price: watts × hours ÷ 1,000 × price per kWh.

And standby consumption?

With the lamp switched off but the power supply plugged in, consumption is 0.2 to 0.3 watts depending on series. Left on the mains continuously for a whole year that comes to around 2.6 kilowatt-hours — less than one euro.

If you want to avoid even that, use a switchable power strip. It is not a must: the time spent plugging and unplugging is worth more than the amount saved.

What follows from this

Service life should not play a large part in your purchase decision — at 25,000 hours all current models are on a par, and the figure is so high that it sets no limit in daily use. Decide instead by lens size, dioptre strength, colour rendering and adjustability. We have separate articles on brightness, colour rendering and dimmability.