LEDs top all bulbs in Which? test, won by company known for data storage. Huh?

Here's some advice for typical consumer confused about the relative merits of all those different light bulbs popping up on retail shelves: The best ones are LED, although not all LED bulbs are created equal, and the top performers still cost a king's ransom by conventional standards.

That's according to the latest ranking by consumer magazine Which?, which tested a mix of 22 bulbs including light emitting diodes (LEDs), compact fluorescents (CFLs) and halogens. The result: Five different LEDs swept the “best buy” category, shutting out CFLs and halogens from the top honours.

In fact, all 13 LED bulbs that Which? tested – including 8 that did not earn “best buy” - outperformed all 6 CFLs and all 3 halogens. The 6 CFLs all bested the halogens.

And in a result that symbolizes the shift away from traditional lighting technology and towards the 'solid state' world of LEDs (an LED is a rudimentary semiconductor, or solid state device) Which? gave top marks to a bulb from Verbatim - a company better known as a manufacturer of data storage devices, including those made with solid state designs.

The Japanese firm's 9.5W, 860-lumen model 52132, also known as the 'Classic A', scored 86 percent. Sylvania's 10-watt 806-lumen Toledo GLS A60 also tallied highly. Which? said the brightness of both roughy equalled that of an old-style 65W incandescent. 

(Paywall terms prevent Lux from revealing the identies of the other bulbs. For a full list and for the impressive 3-page roundup, visit the Which? website, which offers a £1 trial for a month. No Philips LEDs bulbs appear because Philips did not provide Which? with any new models, a Which? spokesperson told Lux). 

But buyer beware: Which? did not weigh price as a factor. That's a good thing for the LED vendors, because four of the five stellar LEDs ranged between £15 and £20 per bulb (£18 for Verbatim's £20 for Sylvania), while one carried a £38 tag.Those are all numbers that might induce altitude sickness in shoppers not long removed from the days of easy to find sub-£1 incandescent bulbs.

By comparison, the Which?-reviewed halogen bulbs all cost a more affordable £2 and the CFLs ranged from £3.50 to £6.00. Only one LED was priced below £10, but that £4 bulb was among the lowest scoring of the LEDs.

In its test, Which? put a premium on efficiency, which factored 31 percent into a bulb's score, and on durability, which comprised 30 percent. Light quality and light output (both compare actual performance to the vendor's claim on the box) accounted for 20 percent and 14 percent respectively. For the final 5 percent, Which? weighed actual power usage versus power usage claimed by the vendor on the bulb's packaging.

LEDs in general only narrowly edge CFLs on efficiency (see Which? chart to the right; both trounce halogens), but with efficiency the heaviest category, that difference pushed LEDs well up the rankings. Six of the 13 LEDs scored a possible 5 out of 5 on efficiency, and four bulbs earned 4 stars. The difference in stars reflects a relative comparison of all bulbs - a performance curve - rather than an absolute.

None of the CFLs came close to 5 stars for efficiency. The top performing CFL earned 3 stars and the others earned only 1 or 2. Three LED bulbs also scored either 'bad' (2 stars) or average ( 3 stars) on the efficiency curve. One of those was the £4 bulb, yet the other two cost £16 and £18 (did someone say buyer beware?).

All 13 LEDs earned 5 stars in durability, while only 2 of the 6 CFLs did. Which? defined durability as a light's ability to last and to maintain its brightness.

While many manufacturers claim a lifetime of 25,000 hours, the magazine tested the bulbs by operating them 2,000 hours and switching them on and off 25,000 times (Which? pointed out that bulbs don't always last as long as manufacturers claim, but it did not single out any culprits).

As a reminder that no new bulb technology is yet equalling the good old glow of the incandescent, none of the 22 bulbs received 5 stars on light quality; 20 received 4 stars, and 2 of the LEDs were average with 3 stars. (Translation: efficiency can be a cold thing!)

The Which? scores did not assess whether a bulb is dimmable, nor did they take into account warmup- times or performance variation in different physical climates.

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Photo: The warm old days. Incandescent bulbs like this one may be falling to energy savers like LEDs, but their inefficiency offered a warmth that modern bulbs don't match. None of the LEDs in the Which? test scored top marks for light quality. Image is from Africa Studio/Shutterstock.

Chart: from Which?