What is a G9 lamp?

G9 is a small push-fit socket with two thin loops of glass or metal that you press straight into the holder — no twisting, no screwing. It runs on 230 volts, so it needs no transformer, and it sits mainly in wall lights and small fixtures.

How to recognize it

Look at the base of the lamp. On a G9 you see two thin loops coming out of the glass like a hairpin, about 9 mm apart — hence the name. You push the lamp straight in and pull it straight out.

Do not confuse it with these two:

• G4 — the same design but smaller, with two straight pins 4 mm apart. It also runs on 12 volts.
• GU10 — two thick pins with a thickened end, which you turn a quarter turn. That is the spot socket.

Why G9 sits in wall lights

The lamp is small and the socket takes up almost no room. In a wall light with a closed shade or a narrow shape, a GU10 with its wide reflector does not fit, and a G9 does. That is the entire reason the socket exists.

With us, G9 is therefore found almost exclusively in the wall lights:

• Edwin — matt black, round, €20.95
• Transfer — bronze, square, €20.95
• Tum — white, round, €30.95
• Kubo — cube, IP65 and therefore usable outdoors, €18.95
• Coen — two-light bronze, €36.95

You usually buy the lamp separately

Five of our fixtures state "G9, not included" and two "2x G9, not included". That means you choose the light source yourself, and with it the light color, the number of lumens and whether it dims.

There is one in the accessories: the G9 LED lamp of 3.5 watts at 2700K, 350 lumens, dimmable, 15,000 hours, €13.95. That is a warm lamp with an output comparable to our smaller recessed spotlights.

The exception is the Coen Smart at €67.95: that comes with two Zigbee light sources, so you do not have to buy those separately.

Why G9 still exists

The socket comes from the halogen era, when you could pack a bright light source into a tiny rod. That was exactly what designers of wall lights and chandeliers needed: light without a visible lamp.

With LED that need has partly gone — an integrated LED is flatter still. Yet G9 remains popular, for the same reason as GU10: the light source is separately replaceable. On a wall light that hangs there for ten years, that is worth more than a few millimeters of extra room. When the LED gives out you buy a thirteen-euro lamp instead of a forty-euro wall light.

Heat is the thing to watch

G9 lamps usually sit in a small, closed shade. The LED itself does not get hot, but the electronics in the base do, and in such a cramped space that heat has nowhere to go. That is why G9 lamps give out early more often than spots with the same specifications.

So check whether the lamp is suitable for enclosed fixtures, and stay within the maximum wattage listed for the fixture. On a two-light wall lamp such as the Transfer Double, the consumption of both lamps adds up.

Dimmable or not

As with every other socket, dimmability sits in the lamp, not in the fixture. A G9 wall light on a dimmer only works if the lamp you push into it is dimmable. If it is not, it will flicker — see Why does your LED lamp flicker?

With two wall lights beside a bed, dimming is almost always worth it. Choose a dimmable G9 and a dimmer with a low lower limit, because two 3.5-watt lamps come to 7 watts together and that is too little for an old halogen dimmer.