Halogen bulbs
Halogen lamps are an improved incandescent: a tungsten filament inside a quartz envelope filled with a halogen gas (bromine or iodine). The halogen cycle redeposits evaporated tungsten back onto the filament, extending lifespan and allowing higher operating temperatures.
Key specifications
| Property | Typical value |
|---|---|
| Efficacy | 15–25 lm/W |
| Lifespan | 1,000–3,000 hours |
| CRI | ~100 (full spectrum) |
| Color temperature | 2,900–3,200 K (warm white) |
| Warm-up time | Instant — full brightness |
| Heat output | Very high — bulb surface 200–500 °C |
| Mercury | None |
| Dimmable | Yes — compatible with standard incandescent dimmers |
Safety: do not touch with bare hands
Never touch a halogen bulb with bare skin. Skin oils contaminate the quartz envelope, creating a hot spot that leads to premature failure or shattering. Handle with gloves or a clean cloth. If accidentally touched, clean immediately with isopropyl alcohol before installing.
Fire hazard
Halogen surface temperatures can ignite nearby combustible materials. Always maintain the clearance distance specified by the fixture manufacturer. Never exceed the maximum wattage rating for the fixture.
Phase-out status
General-purpose halogen bulbs are banned or restricted in the EU (since 2018), UK (2021), Australia (2009), and no longer meeting US minimum efficacy standards (45 lm/W). Specialty forms remain available:
- Automotive headlamps (H1, H4, H7, H11)
- Stage, studio, and flood lamps
- Oven and appliance bulbs
- Heat lamps (food service, bathroom)
Replacing halogen with LED — fixture guide
| Base type | LED replacement | Notes |
|---|---|---|
| GU10 | GU10 LED | Direct drop-in at 230 V |
| MR16 (GU5.3) | MR16 LED (12 V) | Check 12 V driver is LED-compatible; some old magnetic transformers need replacing |
| G9 | G9 LED capsule | Direct drop-in at 230 V; check enclosed fixture rating |
| G4 | G4 LED (12 V) | Requires LED-compatible 12 V driver |