The GLS LED comes of age

The GLS light bulb explained

The traditional filament incandescent light bulb has been a standard for decades and in reality it has not changed much since the day it was invented by Thomas Edison in 1872. It normally takes on a characteristic shape which is  kind of pear shaped with the filament housed inside the class cover and a metal cap fitting  to suit the fixture that it is being used for. For the majority of light bulbs of this type the cap fitting is normally the large bayonet type coded B22/BC  or the Edison Screw coded ES/E27.

But what is this shape of light bulb called? This did not used to be important when there were only one or two shapes of light bulb but now there are many types with the emergence of energy saving light bulb varieties then it is important to have a defined name. The answer is it is called the GLS which stands for, General Lighting Service . This is a name it was crowned with many years ago and has stood the test of time so regardless of whether you think the name is meaningful or correct it is universally known as the GLS certainly by the light bulb manufacturers, distributors and retailers. The GLS was only available as a filament bulb but read on because now there are halogen and GLS LED options.

The Rebirth of the GLS Light Bulb

dimmable energy saving light bulb

With the emergence of the CFL (compact fluorescent lamp) energy saving light bulbs onto the market it seemed that the GLS light bulb had seen its day. The CFL’s are made with U shaped and spirals and it is not possible to fit these into a GLS light bulb cover so it seems that the GLS was going to become history. However, with the streamlining of halogen bulb technology then it is possible now to make a Halogen GLS light bulb that looks and performs almost identically to the traditional incandescent lamp but only  uses 70% of the electricity. Additionally and most importantly the halogen bulb if built to the correct standards will meet the new EU regulations for energy saving which in principle means that they need to be at least a C energy classification.

However with the recent advancements in LED technology it does not stop there. LED bulb technology has meant that it has been prohibitively expensive to make light bulbs of sufficient power to replace the GLS light bulb and the LED technology has been reserved for candle bulbs and other applications where a low output is satisfactory. This has now changed and now a 7W GLS LED can be made at an economical price.


The 7W LED GLS will produce a light output roughly equivalent to a 50w traditional light bulb which is quite acceptable for a host of application and more significantly it will realise a massive saving on electricity consumption.  There is another upside of the LED technology which makes this a good choice when comparing to the CFL. The technology involved in making a CFL dimmable is very complex and accordingly has a high price tag so you would typically pay 4 times as much for a dimmable CFL as opposed to a non-dimmable CFL.  BY contrast the dimmable LED GLS is more easily produced with  the LED technology which means that you are only adding around 25% to the cost of the LED GLS which means that mood lighting can be economical effective and very long lasting.


One thought on “The GLS LED comes of age”

  1. An informative article, but I must point out that Swann invented the filament bulb, apparently about the same time as the Eddison team. Swann sued Eddison and they came to the agreement that it would be called the Swann-Eddison light bulb.

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