Compact Fluorescent Lamps (CFLs)

Quick Guide

Price Guide $5.00-10.00 per bulb (dimmable bulbs may cost more)

Potential savings per bulb $111.00 over life of bulb

Where to Buy Supermarkets, DIY Outlets, Variety Stores and Specialty Lighting Stores

Energy savings use 80% less energy than standard incandescents.

Lifespan A quality CFL will last a minimum of 6,000 hours (some are rated up to 15,000 hours).

Features Many different shapes, styles, sizes and various colours of 'whites'. Low energy consumption – they’re very efficient.

Use them Where light is on for many hours and in low-profile wall and ceiling lights where their size can be an advantage. Floor standing and table lamps. Outdoor paths and flood lighting. In fittings where the bulb sits behind a lampshade and as background lighting.

Don't use them With dimmers (unless you purchase a special dimmer version). With sensors and other electronic switches (unless you choose a special high-switch version suited to these applications). Where the fitting is enclosed with no ventilation (this may shorten the life expectancy of the bulb). For task lighting.

Brief description

Compact fluorescents (CFLs) have been around for nearly 30 years, but they have only recently become a cost effective option. They work the same way as linear fluorescent tubes and now come in a range of shapes and sizes that are far more aesthetically pleasing than older prototypes. The CFLs generally available to consumers are fully self-contained to allow them to be used in existing light fittings as the electronic control gear they need to make them work is built into the base of the bulbs.

Advantages

Compact fluorescent lamps use 80% less energy than standard incandescent light bulbs. Quality CFLs last between 6,000 and 15,000 hours and should withstand at least 3000 switch on/off cycles.

This long life and the electricity savings are the reasons why good quality CFLs work out much cheaper to use than standard incandescent light bulbs in the long term.

CFLs used to only be available in ‘cool stark white’ light colours. But today there are 'warm white' options too that are very close in colour to the light from standard incandescent light bulbs. This gives you the ability to select the right tone of light for the various areas of your home.

CFLs now also come in a wide range of shapes, sizes and with increased functionality and choice. This makes them suited to an ever increasing range of home (and business) applications.

Disadvantages

While the increasing choice and functionality makes CFLs more versatile, it also makes choosing the right light bulb for the job more important.

Standard CFLs are generally unsuitable for recessed down lights with built in reflectors – unless the fitting is designed to take them. If you want to convert the downlight choose a CFL of the same physical size and equivalent light output ensuring it fits within the reflector and provides an air-gap around the base. CFLs take a minute or so to warm up to full brightness, so they are also not suitable for places where instant light is required, like inside a pantry.

Although CFLs produce much less heat than standard incandescent light bulbs, the electronic control components in the base do not withstand heat well. So not all CFLs are suitable for all enclosed fittings that have limited air circulation or heat dissipation (e.g. outdoor bulkhead lights). The light from a CFL is more difficult to focus than that from an incandescent too. This makes CFLs more suitable for general room lighting rather than spot lighting where focused light is required.

Not all CFLs are suitable for dimmers and other electronic switches including proximity sensors, although some special dimmer versions are available and are becoming more affordable for the residential market.

Ongoing development

CFLs are already extremely cost effective, highly efficient and are available for use in an ever increasing range of applications. With CFLs growing in popularity all the time, you can expect even more efficient options that cost less to buy before too long.

Choosing the right CFL for you

Given that CFLs provide far more choices than standard incandescent light bulbs, there are a number of things to consider when choosing the right CFL for your light fitting. The following information should be clearly labeled on the packaging:

The type of base - bayonet or screw base are the most common. Make sure the base fits the light fitting by matching it to the bulb you are replacing.
Light colour. 'Warm white' (2700K) is close to the standard incandescent bulbs most of us are used to. Cooler light temperatures such as “cool daylight” (4000K) are also available and are good for areas where greater contrast is required.
Light output. The packaging should clearly state which incandescent bulb the CFL is designed to replace. For example, a 20W CFL is equivalent to a 100W incandescent bulb.
Functionality. Standard CFLs will not work on a dimmer circuit and if they are used in a high switch area, this will decrease their lifespan. Make sure you choose a bulb with the functionality you need, and, only use as directed.
Quality. Like all products, the quality of CFLs can vary greatly between brands. It's worth checking the life expectancy on the packaging (a quality bulb should last at least 6,000 hours) as well as the supplier’s warranty. We recommend buying a brand you trust.

Dispelling the myths

There's a lot of misinformation surrounding CFLs around safety, light colour and quality issues. Some people worry about the mercury content although CFL bulbs typically contain less than one-hundredth of the mercury of an amalgam filling. Some only remember using CFLs that gave out harsh white light. Today's quality CFLs come in a range of colour temperatures to closely match standard incandescent light bulbs, and a recent Consumer NZ test directly compared a range of CFLs, standard incandescents and new generation halogen bulbs.

To get the facts you need to make informed decisions on CFLs, check out our Myths section of the site.

CFL's and Epilepsy

Approximately 5 per cent of epileptics are diagnosed with photosensitive epilepsy - the name given to epilepsy in which all, or almost all, seizures are provoked by flashing or flickering light, or some shapes or patterns. Both natural and artificial light may trigger seizures.

The frequency of flashing light most likely to trigger seizures varies from person to person. Generally it is between 8-30Hz or flashes per second. As part of their normal operation fluorescent lamps flash on and off very rapidly - CFLs 'flicker' at a rate of more than 20,000 times per second, modern linear fluorescent tubes at more than 5,000 times per second, and older style linear fluorescents at 100 times per second. These rates of flickering are well above the level detectable by the human brain and well above the sensitivity range for sufferers of photosensitive epilepsy.

Researchers have concluded that compact fluorescent lamps (CFLs) are no more likely to be a greater risk to people with photosensitive epilepsy than other lamps. For more information about photosensitive epilepsy click here.

A recent study conducted by the Scientific Committee on Emerging and Newly Identified Health Risks, Light Sensitivity Report, September 2008 revealed that 'while photosensitivity of epileptics is scientifically proven, seizures induced by flicker can be accurately correlated to the frequency only for a small range (3Hz, 15-18 Hz).

What happens to a CFL when it dies?

When a CFL is about to die: