Compact fluorescent lightbulbs

Performance and price have greatly improved since our last test of CFLs.
 
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01 .Long life bulbs

Our tester James and CFLs testing

Since November 2009, incandescent bulbs (apart from a few specialised sizes and types) have not been available for sale in Australia as part of the government’s drive to reduce energy consumption and lessen the impact of electricity production on the environment and economy. They have been replaced by compact fluorescent light (CFL) bulbs in most domestic lighting applications.

Early CFL bulbs, which CHOICE first tested back in 2000, cost up to $20 or more and were slow to warm up to full brightness. Now, cheaper to buy – typically about $5-$10 per bulb – and run, they are also faster to warm up and have fewer failures. We’re only 2000 hours into our testing of compact fluorescent light bulbs but results are encouraging; so far, only three bulbs (each of a different model) have failed.

Incandescent bulbs are still available in very small sizes, but will be phased out as CFLs in these sizes become available.

Phase-out of incandescent bulbs

The Australian government’s incandescent light bulb phase-out program applies Minimum Energy Performance Standards (MEPS) to lighting products. Products that don’t meet MEPS will be restricted from sale.

  • Tungsten filament incandescent general lighting service (GLS) light bulbs (the typical pear-shaped bulbs used in most domestic light fittings) don’t meet MEPS and have not been available in stores since November 2009.
  • From October 2010, MEPS will apply to >40W candle, fancy round and decorative lamps, mains voltage halogen non-reflectors, and extra-low voltage (ELV) halogen reflectors.
  • From October 2012, MEPS will apply to mains voltage reflector lamps, including halogen (PAR, ER, R, etc), and >25W candle fancy round and decorative lamps.
    Depending on when efficient alternatives become available, pilot lamps 25W and below will also be subject to MEPS.

How do they work?

Incandescent bulbs work by passing an electric current through a metal filament, making it white-hot so it gives off light. They’re simple and cheap to manufacture but inefficient to run; most of the electrical energy is converted into heat rather than light. 

CFL bulbs pass a current through a mixture of gases in a tube, causing the gases to emit UV radiation, which makes the phosphor coating on the inside of the tube glow (or fluoresce). This process is much more energy-efficient; it uses only about 20%-25% of the electricity needed to light an equivalently bright incandescent bulb.

 
 

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As most consumers are familiar with incandescent bulbs and how much light these put out, CFL packaging indicates both the actual and equivalent wattages.

Generally, a multiplication factor of five is used, so a 15W CFL is claimed to give the same light as a 75W incandescent. Our testing (along with a recent test by the University of NSW) indicates this is only true in the best cases, particularly after the CFL has been in use for a while. For most bulbs, you’re better off using a more conservative multiplication factor of four – that is, assume a 15W CFL will be closer to a 60W incandescent.

What to look for

Colour temperature CFLs are available in three colour temperatures, which basically means three different types of light. The colour temperature is measured in kelvins and indicated on the bulb and its packaging.

  • Warm White (3000K): yellowish light, similar to that from an incandescent bulb. This is a good choice for living areas and bedrooms, where a cosy comfortable light is desired. All bulbs on test are “warm white”.
  • Cool White (4000K): white light, similar to that from fluorescent tubes, and suitable for offices, kitchens, bathrooms and any other room where a whiter light is wanted.
  • Daylight (5000K or more): blue-white light equivalent to outdoor daylight.

Shape The shape of a CFL isn’t a factor in its brightness, but does determine the direction in which most light is thrown. A folded tube emits most of its light out of the sides and should be installed lengthways so the side faces out. A spiral emits light from its end as well as its sides and end, so is probably a better choice for a downward pointing light fitting.
Dimmable Several types of CFLs are suitable for use with dimmer switches, but check the packaging to make sure you have the right type.
Instant light Modern CFLs activate almost instantly with a reasonable light output, so in most cases they’re suitable for use in stairways, cellars and other areas where you need immediate, bright light. Nevertheless, for these areas and other rooms where you typically only switch on the light for a few minutes, choose a bulb with a faster warm-up time so it reaches maximum output faster.
Light fittings There’s no performance difference between bayonet cap (BC) and Edison screw (ES) mounts on light bulbs. However, the light fitting itself can make a difference – whether it has an effective reflector dish, the size and translucence of the glass and so on. Small enclosed light fittings can trap heat even from a CFL and reduce the bulb life, so these aren’t ideal. If you find a particular light fitting isn’t putting out enough light, a brighter bulb may be the answer, but also consider replacing the light fitting with one that has a better reflector.

Tip

Don’t turn a CFL light on and off any more than you need to, as rapid on-off-on again switching can shorten their lifespan. Switching several times a day is not a problem, and don’t be afraid to turn them off when you leave a room; just avoid doing this several times an hour, day in day out.

We haven’t yet reached the lowest claimed lifespan of 6000 hours, but our results so far give a good indication of how the bulbs are performing.

Scores The overall score is comprised of decrease in luminosity (60%) and initial luminosity (40%). 
Decrease in luminosity score is based on the light output after 2000 hours operation. The closer to the initial luminosity, the better. The lowest-scoring models dimmed to the equivalent of a 60W bulb, or less.
Initial luminosity score is based on the light output of the bulb after 100 hours burn-in. The closer to the luminosity of its claimed equivalent incandescent (typically 75W), the better. The best-scoring models started brighter than their claimed equivalent.
Warm-up time is the time taken to reach 80% of maximum brightness.
Claimed wattage is the labelled actual wattage for each bulb. Our measurements indicate this is a reliable figure.
Claimed life expectancy is the number of hours the bulb should last in normal operation (about five hours on per day). The bulb’s lifetime can be reduced by unusual operation, such as very frequent switching on and off or being situated in extremely cold or hot locations.
Price per bulb is based on what we paid in November 2009. Some come in packs of two.

Compact fluorescent light bulbs table

How we test

Our test is based on the Australian Standard for self-ballasted lamps. The bulbs are a mix of screw and bayonet fittings; all are “warm white”, about 15W, with a claimed equivalent brightness to an incandescent 75W bulb (except the Megaman, which claims equivalence to a 70W, and the Philips Tornado which claims 60W).

Our tester, James Thomson, installs 10 samples of each model in a rig of 150 light fittings, and burns them in for 100 hours. The lights then are put into a continuous switching cycle of 165 minutes on, then 15 minutes off.
Light output James measures the light output of the bulbs after the 100 hour burn-in, then again after 1000 and 2000 operating hours. He then calculates the wattage of an equivalently bright incandescent bulb. All but one of the bulbs on test has dimmed over the 2000 hours, but the best have dimmed by only 10% or less.
Switch-on time is the time taken to start giving out light. In our last test of CFLs, we found some took up to three seconds to activate. However, in this test all the bulbs activated almost instantly, so James hasn’t measured the actual times.
Warm-up time shows the time taken to reach 80% of maximum brightness. Most take about 30 seconds or less, which is a noticeable improvement for CFLs but still much slower than an incandescent bulb, which reaches maximum brightness almost instantly.
Failure rate James checks regularly to see if any bulbs have failed (either dying completely or dimming so much that in normal usage you’d replace it). So far very few have failed, but they’ve only been operating for 2000 hours. The minimum claimed life expectancy for these bulbs is 6000 hours, with some claiming 8000 or even 15,000 hours.

We’ll report again after 6000 hours.

Alternative lighting options

Tubular fluorescent lights have been around for decades and are functionally similar to CFLs. Relatively inexpensive, long-lasting and efficient to run, but aren’t always an aesthetically suitable choice for the home.

Halogen are a more efficient type of incandescent bulb. They have a tungsten element in a small amount of halogen gas, which prevents the evaporated tungsten depositing on the bulb wall so the bulb doesn’t dim over time. They’re about 30% more efficient than standard incandescent bulbs and longer-lasting (typically about 2000-5000 hours) and are available for most types of light fitting. While less energy-efficient than CFLs, halogens are good for accent lighting, and are likely to be found in homes as low-voltage downlights. Don’t assume that low voltage means low energy consumption; a typical low voltage halogen downlight uses about 50W plus another 10W for the transformer for a total of 60W, the same as a normal incandescent bulb. These downlights can be a fire hazard, so gaps must be left in the ceiling insulation around the top of the fitting. These gaps reduce the effectiveness of the insulation.

LED Light-emitting diodes are the newest player in energy-efficient lighting, and may take over from CFLs in the medium term. Extremely energy-efficient and long-lasting (up to 10 times longer than CFLs) and activate instantly. Commonly found in bicycle lights, torches, garden lights and traffic lights, and are now available as downlights, but haven’t made significant inroads yet into commercial or home lighting. This is likely to change over the next few years as LED technology improves and becomes cheaper.

Mercury and CFLs

Concern has been raised over the level of mercury in CFL bulbs and whether this presents a danger when a CFL bulb breaks, or comes to the end of its life, and must be disposed of. The simple answer is no; there is no significant risk to you or the environment, though you should still follow some precautions when cleaning up a broken CFL bulb.

  • All fluorescent lamps and tubes, including the long fluorescent tubes that have been around for decades, contain a small amount of mercury - typically around 5 mg of mercury – by comparison, an old mercury thermometer contains around 500 mg.
  • Coal-fired (particularly brown coal) power stations actually put significant amounts of mercury into the atmosphere. Because CFL bulbs are so much more energy efficient, a power station needs to produce only a fraction of the electricity to power a CFL compared to an equivalent incandescent bulb, so over the life of the bulb, the overall amount of mercury put into the environment is greatly reduced, even allowing for the small amount of mercury in the CFL bulb itself.

Nevertheless, a broken CFL bulb can release mercury into the air. The health risk from occasional breakages is very low, but it’s still important to treat the broken bulb safely.

  • Open windows and doors to ventilate the room for 15 minutes before cleaning up the broken bulb. \
  • Wear disposable gloves and sweep up the pieces with a disposable brush if possible. Put the broken pieces in a sealed container.
  • Use sticky tape or a damp cloth to pick up any dust and small pieces. If vacuuming is still needed (such as on carpet), dispose of the bag afterwards, or empty and wash the collector bin.
  • Dispose of the clean-up gear and broken pieces in your regular rubbish, not in recycling. Likewise, dead (unbroken) CFL bulbs should be wrapped and put in regular rubbish, unless your local council has different rules.

Use "mercury" to search for more information on mercury in CFLs and correct disposal.

The environmental benefit of the phase-out of inefficient lighting has been widely publicised, but CFLs aren’t without impact — they use more energy to produce and contain mercury, which could spell problems if it’s not recycled. So what’s the overall verdict?

A life cycle analysis of CFLs published last year in The Environmental Engineer concluded that CFLs are the better choice for the environment, mainly because of their much more efficient use of electricity. As for the mercury they release at the end of life, the analysis found that the production of incandescent lamps contributes five times more mercury from burning coal for electricity. This was even the case in Tasmania, where hydroelectricity dominates, although involving much smaller quantities.

Environment groups are generally supportive of the initiative overall. “CFLs are not completely green in every way, but on balance they have a much lower impact than incandescents,” according to the Australian Conservation Foundation.

Did you know?

  • Up to 90% of the energy an incandescent (standard) light bulb uses is wasted, mainly on heat.
  • Lighting represents around 12% of Australia’s domestic greenhouse gas emissions.
  • Globally, electric lighting generates emissions equal to 70% of those from all passenger vehicles.
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