It doesn't matter, really. G9s were originally halogen bulbs. If you use a G9 led in a fitting designed for a halogen lamp it will have a short life as it will overheat, as most of those fittings have nowhere for the heat produced to escape (even the small amount produces by a 4W led).
I have G9 light fittings (originally halogen-based) in the kitchen, and have been disappointed with the light level from "equivalent" lumen leds, and their life. The trouble is, I could get brighter leds with a higher lumen output, but they'd run hotter and burn out more quickly. I'm thinking of changing the fittings to GU10.
In general, they produce less heat than their halogen equivalent, so where's the problem? Certainly the one on this desk allows me to touch & hold the metal shade which I could never do withn the halogen one.
If the led points up in an open fitting, even made of glass or other poor heat conductor there shouldn't be a problem, as the heat produced by the electronic power supply in the base of the lamp can escape. However, if the bulb is fully enclosed, or points down in an unventilated holder, the heat produced by the power supply in the base has nowhere to go. If you feel the base of a 4W led in such a holder after being on for a few hours, you will find it is on the warm side.
Your metal shade is a good conductor of heat, so any heat produced by the led dissipates quickly. Try the same thing with a glass shade and you'll soon see the difference.
I have foolishly installed four light fittings with G9 LED bulbs. I?m fed up playing the bulb changing game. Seriously thinking about just going back to halogen or ditching the lights.
Surely if the leds get hotter than a halogen there is something v very wrong somewhere. Could it be down to the space needed to get the power supply bit into? Brian
G9 led bulbs that I got from Ledhut were constantly blowing but the cheap never-heard-of-brand replacements that I got via Amazon nearly two years ago have been trouble-free in the same fittings and I've not had to use any of the spares that I bought just-in-case. THey are brighter as well.
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