What is a GLS bulb?

What is a GLS bulb?

The GLS bulb is a traditional design of light bulb. It has been in use for over a century, and is probably the most well-known bulb shape in the world. It has the classic, pear-like bulb shape. Its shape is versatile, and it is still one of the most popular types of lightbulb available today.

The more modern GLS bulbs are often opaque (described as ‘pearl’ or ‘opal’) and are made from heat-resistant thermal plastic or glass.

Its versatility allows it to be used in a variety of lighting fixtures.

GLS light bulbs are fitted with one of two types of cap:

  1. a B22 bayonet cap often abbreviated to BC – it is a push and twist style of cap
  2. or an E27 Edison screw (ES) base, which obviously screws into the light socket
Frosted GLS light bulb BC/B22 bayonet typeFrosted GLS light bulb BC/B22 bayonet type
Frosted GLS light bulb ES/E27 screw typeFrosted GLS light bulb ES/E27 screw type

The GLS lamp is the most recognised light bulb today. It is so common it has become iconic

In the UK, version one is more common, the BC cap type, and still is common, even in new build properties. The screw type is found across the USA and Europe.

The GLS lamp is the most recognised light bulb today. It is so common it has become iconic. So, when you see ad campaigns on billboards or on the telly, or online, it’s normally the GLS pear shape that you see as an outline.

Thomas Edison is usually associated with inventing the GLS bulb, but this is not true. The common light bulb was a long collaboration of efforts between physicists and chemists including Joseph Swann and Charles Strearn. In fact, the first street in the world lit by an incandescent lightbulb was Mosley Street in Newcastle upon Tyne, in 1879.

GLS stands for General Lighting Service. By 1885, Edison had patented the pear-shaped light bulb and his company General Lighting Service had sold more than 88 million standard bulbs by 1914. By the end of World War Two, nearly a billion had been sold and GLS had become standard parlance and iconic.

GLS light bulbs are everywhere, and easily found in various styles. The old ‘Incandescent GLS light bulbs’, were banned across the EU by 2019. In the UK they were phased out by 2011 and replaced by the more cost -effective LEDs, which require lower amounts of electricity to achieve the same number of lumens (brightness).

The distinctive yellow LED filament bulbs are a fashionable choice, so designed to imitate the filaments of the traditional incandescent GLS from the 1920’s and 30’s.

There is a choice too, of traditional GLS style in a more amber coloured glass with an Edison screw cap (E27)

There are dimmable bulbs designed specifically for that technology too.

See our bulb section in the main menu for our selection of more bulbs and LED’s.