Lighting – What’s the difference between dimmable and non-dimmable LED lamps

energy efficiencyledlighting

I have a large room in my house with 3 light fittings, with a total of ten 40W GU10 bulbs. So, this is using 400W when they're at max output (they're all on dimmer switches).

I'm interested in reducing this by replacing the bulbs with LED's (or some other dimmable low power alternative) as the ones I have fail over time.

So, I'm curious as to why dimmable GU10 LED lamps are so expensive. £20-£25 is the best price I can find.

Best Answer

The two differences are

  • Cost
  • It can be dimmed with a standard dimmer

A standard dimmer reduces the RMS voltage going to a light to dim it; this may be done by a simple resistor or by chopping of the top of the waveform. So a dimmable LED lamp must be able to:

  • Cope with a big range of input voltage including part formed sine waves, which isn't easy for the control logic.
  • Detect from the input voltage the light level that the user wants, then give that light level.

It would be a lot better if a dimmer switch could send a digital signal (radio, or over the main wiring) to the lamp, so that the lamp could know what was required without reverse engineering the voltage back to the user's wishes. However this would need a new standard to be used by all switch and lamp vendors, so may take a little time-:)

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