Choosing Compact Fluorescent Lamps (CFLs)

Although they have been superseded by LED light bulbs, compact fluorescent lamps (CFLs) can still save a significant amount of energy compared to traditional incandescent and halogen light bulbs.

There is a compact fluorescent alternative to pretty much any standard light bulb, in addition to specialist 'push-fit' CFLs that are designed to be used in shaver lights and cabinet lights, for example. Push fit CFL lamps are available with a variety of different caps, which all look similar but are not interchangeable. Our article about light bulb fittings, caps and bases goes into more detail about the different kinds of push-fit lamps you can find.

Replacing light bulbs with CFLs

If you've seen a CFL before, you will have noticed that they don't look like standard light bulbs at all. Unlike incandescent bulbs, for instance, which house a heat- and light-generating filament within a glass envelope, CFLs are simply smaller, turned versions of the long fluorescent tubes you might have seen in car parks and offices (hence their name).

Not all CFLs look the same, either: those that are designed to replace standard GLS bulbs look like spirals, while push-fit CFL tubes have just one or two turns to them.

So how do you make sure you pick the right CFL?

Start with the cap type

Determining what type of cap your current light bulbs have - and the type your new bulbs need - will largely dictate the kind of CFL that will be available to you. For example, if you know that you need a light bulb with a B22d bayonet cap (BC), your choice of CFL is narrowed down to spirals and certain designer bulbs.

On our site, you can use the main menu to search for the correct cap type, then filter the results by 'Technology,' making sure to choose compact fluorescent/CFL. After that, it's simply a case of refining your selection further (by wattage, energy rating etc) to find the ideal bulb.

Choosing push-fit CFLs

Getting the right type of push-fit CFL is slightly more complicated, firstly because of the variety of very similar bases they have, but also because more often than not, they are used in luminaires containing control gears designed to match the characteristics of the lamp.

Push-fit lamps are also known as PL lamps (after Philips Lighting), and come with either 2-pin or 4-pin bases. Some 4-pin lamps are dimmable, providing that the control gear of the light fitting is suitable, whereas all 2-pin push fit lamps are non-dimmable.

The easiest way to find the right PL lamp is to check the light fitting for details of which are compatible with it. If you still have the old lamp, you can check it against our examples to find the right one. The base or cap should be one of the below. Be sure to check carefully, as the visual difference between some models is only slight.

push fit cap types