What bulb should you use in an outdoor pendant light?

LED is the only bulb type worth specifying for an outdoor pendant light. It runs cool, tolerates the repeated cold starts that exterior fittings see through a British winter, and delivers full output instantly at temperatures where halogen and filament bulbs struggle or fail outright. Most outdoor pendant fittings take either an E27 screw bulb or a GU10 capsule; both are widely available in LED form, and a quality LED rated for enclosed fixtures will last 15,000–25,000 hours against roughly 2,000 for halogen. The fitting itself matters as much as the bulb: anything mounted outside needs at least IP44, which protects against splashing water from any direction, and the bulb must sit inside that protected envelope rather than protruding past the diffuser. When we specify outdoor pendant lights for a porch or covered patio, we match the bulb base to the fitting's marking on the lamp holder — never assume E27. The same enclosure principles that govern downlighters indoors apply outside, and Electrical Safety First's guidance on installing downlighters explains why fire and moisture ratings must be respected together. Halogen remains legal but is obsolete here: it runs hot, draws five times the power for the same lumens, and its filament is fragile under wind-driven vibration.

Start with the fitting's maximum wattage marking, stamped on the lamp holder or backplate, and never exceed it — but with LED, treat wattage as a ceiling rather than a target. A 5W LED produces roughly 470 lumens, equivalent to a 40W incandescent, and that is enough for a standard porch or doorway. For a pendant hanging over an outdoor dining table or seating area, step up to 800–1050 lumens (7–9W LED) so the light reads as a feature rather than a faint glow. As a working guide: - Porch or entrance: 470 lumens, 2700–3000K - Covered seating or dining: 800–1050 lumens, 3000K - Security-adjacent placement: 800+ lumens, 4000K Check the bulb's physical size too. Outdoor pendants often use closed glass shades, and a bulb that is too long or too wide will foul the diffuser or trap heat. A19 or golfball-format LEDs suit most enclosed fittings; stick-format bulbs generally do not. If the pendant is on a PIR sensor or photocell, confirm the LED is compatible — some budget LEDs flicker or cycle on low-current standby circuits.

Colour temperature is measured in kelvin (K), and for outdoor pendants the choice sits between 2700K, 3000K and 4000K. Use 3000K warm white as the default for anything a person stands under or sits near: it renders skin tones and brickwork naturally and matches the interior lighting visible through the doorway, so the transition from hall to porch does not feel jarring. Choose 2700K only where the pendant is purely decorative and you want a candle-like glow. Use 4000K cool white where the pendant's job is visibility rather than ambience — above a side gate, a bin store, or a driveway approach — because cooler light improves contrast and makes faces and number plates easier to identify. Avoid anything above 5000K: it reads clinical, washes out colour, and attracts more insects. Consistency matters across a scheme. If the pendant sits alongside wall lights or bollards, specify the same colour temperature throughout, because a 3000K pendant next to a 4000K bollard looks like a fault rather than a design decision. CRI (colour rendering index) is worth checking too: choose CRI 80 or above so foliage, timber and masonry render accurately.

An IP (Ingress Protection) rating is a two-digit code: the first digit covers solids, the second covers water. Outdoor pendants need IP44 minimum, which resists splashing water from any direction — adequate for a covered porch or under a soffit. For exposed positions such as an open pergola or coastal frontage, specify IP65. The bulb must stay inside that protection: an exposed E27 cap outside the gasket is a failure point regardless of the fitting's rating. Practical checks before and after installation: - Confirm the bulb is rated for enclosed fixtures if the shade is sealed - Inspect the door gasket and cable gland annually and replace any perished rubber - Apply a dab of silicone grease to the gasket to keep it supple - Point the lamp holder drain hole (if present) downward so condensation escapes Water finds its way in through the cable entry more often than through the glass, so a compression gland with a proper cord grip is essential. The zone-based approach used for wet rooms applies outdoors too — the bathroom safety zones explained by Electrical Safety First mirror the logic of keeping mains-voltage parts away from where water collects. Finally, isolate the circuit at the consumer unit before any bulb change.