GLS LED Bulbs

What is a GLS light bulb?

GLS stands for general lighting service, the trade name for the standard household bulb with a rounded head that narrows down to the cap. It is the shape people usually picture as a light bulb, at home in ceiling pendants, table lamps and floor lamps. Almost all of the bulbs on this page are LED versions of that shape.

Size matters too. Almost all of ours are compact, and some are a larger medium size that looks good where the bulb is on show, so measure the space inside your shade or fitting and check the bulb's size before ordering.

E27 or B22: which cap does your GLS LED bulb need?

The cap is the base of the bulb, and it must match your lamp holder. An E27 cap screws into the holder, while a B22 cap is a bayonet with small side pins that you push in and turn to lock. In both names, the number is the cap's width in millimetres. Most of our GLS LED bulbs have an E27 screw cap and many have a B22 bayonet cap, the caps found most often in UK homes.

They are not interchangeable, so switch off, let the old bulb cool and check its base: a threaded base is a screw cap and side pins mean a bayonet. Both types also come in smaller sizes, so match the letter and number exactly.

How bright should a GLS LED bulb be?

With LED, watts tell you how much power a bulb uses rather than how bright it is, so compare lumens instead: the higher the lumens, the brighter the light. Most of our GLS LED bulbs draw under ten watts, and many draw between ten and twenty-five watts. Many are suited to ambient lighting, the general background light that fills a room.

As a guide, a bedside or hallway lamp needs less light than a kitchen or study, and a thick fabric shade soaks up more light than an open fitting. Check the maximum wattage marked on your fitting or lampshade and stay within it.

Warm white, cool white or daylight GLS LED bulbs?

Colour temperature, measured in kelvin, describes how warm or cool the white light looks: the lower the figure, the warmer and more yellow the light, and the higher it is, the crisper and bluer. Most of our GLS LED bulbs are warm white, the soft, relaxed light closest to an old incandescent bulb, which suits living rooms, bedrooms and dining rooms. Many are cool white, a fresher, more neutral tone for kitchens, studies and utility rooms, and many are daylight, the crispest white, often chosen for reading, hobbies and workspaces.

Many give a very warm white, a deeper glow with a hint of amber. A few let you adjust the white between warm and cool, a few are RGB bulbs for coloured light, and a few are smart bulbs; check the product details for how each is controlled. For an even look, keep to the same colour temperature across a room.

Opal or filament: which GLS LED bulb finish suits your light?

Many of our GLS LED bulbs have an opal finish, a milky white cover that spreads the light evenly and hides the LEDs inside. That makes opal the easy choice under a lampshade or inside a closed fitting. Many have a filament finish instead, with slim LED strands on show, in the style of an early electric bulb. Filament bulbs are made to be seen, so they suit open pendants, cage fittings, bare-bulb lamps and glass shades.

Many of our GLS bulbs have a vintage style, and a few have a gold or amber finish that suits that look. A few have a frosted finish, which softens the light in a similar way to opal.

Can GLS LED bulbs be used with a dimmer switch?

Only if the bulb is dimmable. Most of our GLS LED bulbs are non-dimmable, but many are dimmable, so check the product details before ordering for a light on a dimmer. A non-dimmable bulb on a dimmer circuit can flicker, buzz or fail early, and even a dimmable bulb works best with a dimmer switch made for LED loads. Older dimmers designed for incandescent bulbs often need a higher minimum load than LED bulbs draw, which can cause flicker at low settings.

If you need to replace or add a dimmer switch, we recommend a qualified electrician. In England and Wales, work on fixed wiring falls under Part P of the Building Regulations, and an electrician can make sure the switch suits the bulbs and the load on the circuit.

What to check before buying GLS LED bulbs

Before ordering, match the cap to your lamp holder, check the bulb's size against your shade and choose a bulb marked dimmable for any light on a dimmer. Many of our GLS LED bulbs carry an IP20 rating, which means they are for dry indoor fittings. In a bathroom, the fitting itself must be rated for its zone, so check that first.