Light bulb types
The technology inside the bulb determines efficacy, lifespan, heat output, and dimmability. The base type is a separate question — see Bulb Bases for socket compatibility.
Quick comparison
| Type | Efficacy | Lifespan | CRI | Dims? | Mercury |
|---|---|---|---|---|---|
| LED | 60–150 lm/W | 15,000–50,000 h | 80–95+ | Yes (LED dimmer) | None |
| CFL | 40–70 lm/W | 6,000–15,000 h | ~82 | Dimmable models only | 3–5 mg |
| Halogen | 15–25 lm/W | 1,000–3,000 h | ~100 | Yes | None |
| Incandescent | 10–15 lm/W | 750–1,000 h | ~100 | Yes | None |
Bulb types in detail
LED
Best all-around choice. Highest efficacy, longest lifespan, available in every color temperature. Works with most existing fixtures. Requires LED-compatible dimmer for dimming.
CFL
Compact fluorescent. More efficient than halogen or incandescent, but slower start, mercury content, and being replaced by LED in most new applications.
Halogen
Near-perfect CRI, instant brightness, excellent color rendering. High heat output and short lifespan. Being phased out in most markets.
Incandescent
Excellent CRI (~100), warm familiar light. Lowest efficacy of any bulb type. Banned for general use in most countries; specialty forms still sold.
Comparisons
Not sure which base your fixture uses? The bulb technology and the base standard are independent. See Bulb Bases for E26, GU10, G9, and all other socket types.