Lightbulbs

Lightbulbs

Two things identify a light bulb: the cap that fits the holder and the shape of the glass. B22 is the bayonet cap that pushes and twists, E27 is the large screw cap, and their small versions are B15 and E14, with GU10 the twist-lock cap used in downlighters and spotlights. Shape then follows the fitting: GLS is the classic pear-shaped bulb, candle bulbs suit wall lights and chandeliers, golf ball bulbs are the small round ones, and filament bulbs show a visible LED strand for an exposed fitting. LED bulbs are now sold by both actual wattage and the old incandescent equivalent, so a 9.6W LED is sold as a 60W replacement, and lumens are the honest measure of brightness at roughly 470 lumens for a 40W equivalent, 806 for a 60W and 1521 for a 100W. Warm white is the standard domestic colour. Alongside the general lighting sit the specialists: heat resistant oven bulbs, infrared heat lamp bulbs, striplights, night light replacements and WiFi smart bulbs.

Eveready covers the broadest spread, with GLS LED bulbs at 5.5W, 9.6W, 10.8W and 14W in both B22 and E27 as 40W, 60W, 75W and 100W equivalents, candle bulbs at 6W in B22, B15, E14 and E27, golf ball bulbs in B22 and E14, GU10 spots at 3W and 3.8W in warm white, plus a 25W E14 heat resistant oven bulb, an 18W 4-pin PL-T and night light replacement bulbs. Energizer handles the lumen-rated range with 7.3W 806 lumen E27 and 12.5W 1521 lumen B22 and E27 bulbs, dimmable B15 filament and standard bulbs at 470 and 550 lumens, a 9W 60W B22 four pack, a clear candle bulb and a 310mm S19 striplight. Wiz supplies WiFi smart bulbs in A60 classic white B22 and ST64 amber white E27, Solas the 250W ES R125 infrared heat lamp and its protection basket, and Evolec a 3W B22 flicker flame bulb.