Light bulb types: LEDs, bases, and Kelvin explained

Check three elements in order: the technology (LED, the only one still relevant), the base that must fit your socket (E27, E14, G9, G4, GU10) and the colour temperature in kelvins. This trio settles almost every choice; shape, glass and wattage are just decoration.

What are the 4 types of light bulbs?

Four types of light bulbs coexist: LED, compact fluorescent, halogen and incandescent. Only LED is still sold and genuinely relevant: it switches on instantly, heats very little and uses around 90% less than an incandescent bulb. Halogen and incandescent have been withdrawn from the European market because of their poor efficiency.

Compact fluorescent, known as low-energy, retains a residual place: it takes a few seconds to reach full brightness and contains mercury. LED solved both drawbacks at once.

To light a whole house, LED covers every room, from the ceiling light to the smallest spotlight: it is the basis of every lighting range today.

The switch to all-LED happens as bulbs fail, without replacing everything on the same day, as long as you keep the same base.

Our LED bulb collection has 266 references as of 23 September 2026, enough to find the exact equivalent of every old bulb.

What are the drawbacks of LED bulbs?

Three reservations come up: uneven light quality depending on the model, a sometimes overly cold rendering, and entry-level references that are incompatible with a dimmer. Check the "dimmable" mention before buying if you light with a dimmer.

This matters for a living room or bedroom, where the mood is often adjusted. Our guide on the dimmable or variable-intensity bulb details the compatibilities.

What are the different types of light bulb bases?

Two main families: screw bases (E27, the large one; E14, the small one) and pin bases (G9, G4, GU10, GX53). The letter indicates the fitting method, the number the diameter or spacing in millimetres. An E14 is 14 mm wide, a G4 has 4 mm between its two pins.

In a survey of 33 bulbs from our catalogue as of 23 September 2026, the E27 base fits 42% of references, ahead of G9 (27%) and G4 (24%). The E27 therefore remains the format to know first.

Once the base is identified, replacement comes down to wattage and colour. Our E27 base bulbs cover most pendants and table lamps.

How do you identify a light bulb base?

Look at the base of the used bulb: a wide thread is an E27, a narrow thread an E14, two small pins a G4 or G9. If in doubt, compare the old bulb and the socket before buying.

The full reference is often on the base or the packaging: base type, wattage, voltage. Our article on light bulb size and base shows how to read these markings.

What is the standard light bulb base?

E27 is the standard base in France: the large 27 mm screw base found on most ceiling lights, pendants and lamps. E14, its narrow version, is mainly used on small lamps and some wall lights.

How do you know which type of bulb to use in each room?

Match the colour temperature to the room's use. Warm white (2200 to 2700 kelvins) for a living room or bedroom where you relax, neutral white (3000 to 4000 K) for a kitchen or bathroom where you need to see accurately. The base depends on the light fitting.

The lower the kelvin number, the more the light leans towards warm yellow; the higher it goes, the whiter it becomes. The choice between white or yellow light is decided room by room.

Our catalogue data confirms this residential use: in the same survey of 33 bulbs as of 23 September 2026, 61% are associated with the living room and 58% with the bedroom. These are the two rooms where designer LED is most often used.

Unsure between an E27 base and a G9, or about the right light temperature? You can talk to our decor advisers to decide before ordering.

With LED, wattage is measured in lumens rather than watts: the same base covers a wide range of brightness, so aim for the mood you want.

To decide between two ambiences before buying, the selection is reviewed by buyers, and the Designix Google listing gathers their public reviews.

Which bulb shapes should you choose for your light fitting?

Shape is chosen after the base, depending on whether the bulb stays visible or not. A visible bulb in a pendant without a shade calls for a beautiful globe or a decorative filament; hidden behind glass, a standard shape is enough. Globe, tube, candle and sphere are the common silhouettes.

The LED filament reproduces the warm rendering of old Edison bulbs, without their consumption. To match shape and temperature to the place, see our pointers on decorative bulbs and temperature by room.

In terms of material, this survey of 33 bulbs as of 23 September 2026 leans towards glass (61%) and metal (42%), finishes that stand out when the bulb is exposed.

One reflex avoids the mistake: technology, base, temperature, then shape. Our guide to choosing bulbs well takes you through the method from start to finish.