Efficient Bulb Test

Test: Bill Whitley, Consumer NZ, 2011.

CFL bulbs give plenty of light and save you money

But you need the right bulbs – there’s still a big difference between the best and worst on the market.

Consumer last tested compact fluorescent lamps (CFLs) in June 2009 (Consumer 492). They found then that good-quality CFLs were brighter, lasted far longer and used much less electricity than old-school incandescent bulbs.

Two years on, the mix of CFLs on the market has changed – but their test results still show a wide variation in performance.

Testing

What Consumer did

Consumer chose 19 CFLs. All but two claimed to be a replacement for a traditional 100W incandescent bulb. Thirteen were rated at 20W and six at 18W. All were warm white.

The CFLs were mainly spiral tubes but there were also four “stick” (U-tube) types and two covered globes (the ones that look like a traditional bulb). The spiral shape has pretty much taken over the home-CFL market because it gives a more even distribution of light than the earlier U-tube style, which tends to spray most of the light sideways. The spiral shapes were the best performers in their test.

Light output

Consumer wanted to see if the CFLs were as “bright” as the bulbs they replaced. They put two samples of all the CFLs into a special test rig and compared the light output of each model with the averaged light output from eight different 100W incandescent bulbs. This averaged “incandescent” figure formed the baseline – and the light output of the CFLs is their relative performance against this baseline.

Switching life

Consumer also put three samples of 19 of the CFLs into a special rig which switched the bulbs on for five minutes and off for five minutes 6000 times – nearly six weeks of on-of cycling. The bulbs were continuously monitored so that they could tell if and when they failed. They tested only 19 bulbs for this because the Panasonic CFL wasn’t available for the start of the test.

Light output

Of the original 19 bulbs, 9 were brighter than the average-light baseline and 10 weren’t.

The Philips Tornado had the highest light output: it was 26 percent brighter than the baseline. It was followed by the GE Entice and the Osram Duluxstar Mini Twist. The Philips Tornado Dimmable also performed well: it gave 16 percent more light than the baseline. They recommend it (for dimmer use), although it’s not cheap.

The worst performers were the two covered globes: the Philips Ambiance (65 percent) and Marexim Safety Bulb (60 percent). From these results, it’s clear you should only use covered globes where you want the look of a traditional bulb. If you want the same light output as spiral- or stick-shaped bulbs, you will need a higher wattage covered globe.

Long life

To pay for themselves in energy savings, CFLs need to last as long as possible.

Eleven models had no failures during the 6,000 on-off cycles and four models – the Edapt Spiral and 3U, the Essentials and the Osram Duluxstar Mini Twist – had all three of their samples fail.

There was a pattern to the failures: the more expensive big-name brands usually lasted longer than the lesser-known or “home” brands. But the $7.85 Osram Duluxstar Mini Twists were disappointing for a major lighting brand.

Consumer's findings

• Good CFLs produce at least as much light as the old-school incandescent bulbs they replace.
• You can be confident that a good- quality CFL will last well, even if it’s frequently switched on and off.
• In most cases, major-brand CFLs last longer than cheaper brands.

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