Fluorescent light is created when electric current is applied to mercury vapour, producing an ultraviolet light that causes the coating inside the lamp to glow.
As the name suggests, compact fluorescent lamps (CFLs) are coiled or spiral fluorescent lamps. CFLs come in several different shapes, such as:
Fluorescent tubes are usually straight or circular, and come in different sizes. They also come in a range of colours, from cool white (suitable for kitchens and bathrooms) to warm white, which takes on a yellowish tone (suitable for living areas and bedrooms).
Many of the problems associated with fluorescent tubes in the past – the appearance, slow start-up and warm-up times, flickering, and sometimes an audible hum – meant that fluorescent tubes were not a common lighting choice in homes. However, specialist lighting stores have a wide range of modern fluorescent fittings now suitable for use in homes. Fittings that use the slim-line T5 fluorescent tubes start almost instantly when switched on and have no flicker.
It uses around one fifth of the power used by incandescent lighting – an electric light with a wire filament heated until it glows. Typically, fluorescent bulbs last for 6000 to 8000 hours, whereas incandescent bulbs generally only last for around 1000 to 2000 hours. One of the main reasons CFLs are so efficient is that most of their energy is used to solely create light, rather than creating light and heat, as less efficient forms of lighting do.
Although CFLs are slightly more expensive to buy than incandescent bulbs, their longer life and lower energy usage make them less expensive over their lifetime. Fluorescent lighting will save you money.
CFLs and fluorescent tubes can be used in all areas of your home, but they generate the biggest savings if used in areas where lights are left on for long periods of time. This includes living rooms, kitchens, laundries, playrooms, hallways, garages and other external areas.
What is the light output of the new lamp?
The CFL packaging will usually show you the equivalent wattage to an incandescent bulb.
What is the expected lamp lifetime?
A good quality CFL should last for 6000 to 8000 hours, much longer than an incandescent bulb, meaning it will need replacing far less often.
Are there a range of colours?
Yes, there are warm and cool white CFLs available. Warm white (yellowish light similar to an incandescent globe) is generally preferred in the main living areas and bedrooms, but cool white is usually acceptable in kitchen and bathroom areas.
What is the fitting at the base?
CFLs have either a bayonet or Edison screw base. Take your old bulb to the shop to make sure you don't buy the wrong one.
Will the CFL be compatible with the size and shape of my existing light fitting?
CFL lamps come in many sizes and shapes, so it shouldn't be a problem finding one to fit your light fitting.
Is the warm-up time acceptable?
Although CFLs are generally slower to warm up to full brightness than other types of lighting, the newer CFLs have much shorter warm-up times.
Enclosed or downlight 'can' fittings
Not all CFLs are suitable for use in enclosed or downlight 'can' fittings.
Can the lamp be used on a dimmer circuit?
Standard CFLs are usually not suitable for use with lighting dimmers. Special CFLs with dimmers are available, but they tend to be more expensive. Check the packaging.
Replacing 12V downlights
If you are replacing 12V downlights, make sure the size and shape of the replacement CFL lamp is compatible with your existing fitting.
Try before you buy
Before you buy a complete set of CFL replacements, buy one lamp and check that:
The Light Bulb Saver App identifies the best light bulbs to replace incandescent and halogen bulbs, and can help you calculate your savings by switching light bulbs. It also provides tips about choosing the right lighting for each room in your house.
Download the free app from iTunes or Google Play.