Types of Compact Fluorescent Lamps

Compact fluorescent lamps (CFLs) are a highly energy efficient alternative to incandescent lighting that have been used for many years.  They have been designed to provide a strong source of light whilst using less electricity.  CFL lighting technology over previous years has become a popular choice of lighting in domestic and commercial properties alike.

Compact fluorescent lamps are made from a fluorescent tube that is folded or shaped to create a smaller, more compact form. This compact design allows them to fit into a wide variety of fixtures making them a good choice of lighting for many different lighting fixtures.  

CFL lamps are available in several different formats depending on the fixture, ballast type, and application they are being used for.  Some lamps are specifically designed for plug-in fittings used in commercial lighting systems and others have been shaped to provide broad, even illumination in ceiling fixtures and bulkhead lights.

It is important to understand the different types of compact fluorescent lamps that are available in order to help you choose the correct replacement for your lighting system.  We have put together this FAQ to help highlight the differences between the different options available and for you to choose the correct replacement light.

PL-C Lamps

PL-C lamps are one of the most common types of compact fluorescent lamps. They have a compact folded design which is made of parallel tubes connected to a base enabling them to be a good balance between light output and size making them a popular choice for a wide variety of lighting fixtures.  They are often found in recessed ceiling lights and commercial downlights.  

PL-C lamps are available in both 2-pin and 4-pin versions meaning you might find this type in fittings that use magnetic or electrical ballasts.   A 2-pin version will work with a magnetic ballast and a 4-pin version will work with an electronic ballast.

PL-S Lamps

PL-S lamps are smaller compact fluorescent lamps designed for lighting fixtures where space is limited. Their compact design makes them suitable for smaller lighting units and decorative fittings that do not have the space for the larger lamp types.  The PL-S lamps still offer great energy efficiency despite their smaller size akin to the larger types of CFL lamps. 

These are also available in 2-pin and 4-pin versions and much like PL-C lamps a 2-pin version will be suitable to work with magnetic ballasts and 4-pin versions would work with electronic ballasts.

Because of their smaller size, PL-S lamps are often chosen for installations where a discreet lighting solution is required whilst still having improved energy efficiency compared to incandescent lights.

PL-L Lamps

PL-L lamps are a larger type of compact fluorescent lamp which has been designed to deliver higher levels of light output. These lamps have a longer tube design meaning that they can produce more illumination than other smaller CFL lamp types.

These lamps are most commonly used with electronic ballasts and have 4-pins.  Their longer tube design helps to improve light distribution making them a better choice for commercial lighting systems that need a higher level of brightness.  They are frequently used in professional working environments such as offices and educational buildings.

PL-T Lamps

PL-T lamps are also commonly used in commercial lighting systems. These lamps have a compact triple-tube design that produces strong illumination while using a smaller amount of electricity compared to an incandescent equivalent.   PL-T lamps are a popular choice of lamp where balance between lamp size and brightness is needed.  This includes recessed ceiling fixtures and downlights.

PL-T lamps are also available in both 2-pin and 4-pin configurations, allowing them to work with magnetic and electronic ballast types depending on the lighting fixture.

2D Light Bulbs

2D light bulbs are a distinctive type of CFL lamp known for their flat, square-shaped design which looks like two capital letter D’s next to each other.  2D lamps are made with a single continuous tube which is then bent into a square or rectangular shape.  The shape of 2D lamps allows them to produce a wide and evenly spread source of light making them ideal for ceiling fixtures and bulkhead lights where a wide light distribution is important.

The flat shape of 2D lamps makes them suitable for slim lighting fixtures meaning that they are a good choice for a bright source of light that can fit into a compact space.  They are available in a wide variety of wattages and colour temperatures allowing the user to choose the desired level of lighting.  

It is worth noting that you cannot choose a different wattage to one you had previously if you are looking to replace a 2D lamp as the fittings are designed with a particular wattage in mind.  The wattage of this type of lamp will dictate what size it will be.

Choosing the Right Type of Compact Fluorescent Lamp

When selecting a replacement compact fluorescent lamp you should pay attention to the pin configuration; wattage, fitting type and the ballast used within the lighting system.  Each type of CFL format is designed for a specific fitting so you will need to use the correct lamp to ensure that it works correctly within the fitting. You may also want to consider if you want the colour temperature to match or if you would like something different.  The colour temperature will be labelled as anything from 2700k (warm white) to 6500k (daylight).