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Philips SlimStyle LED review: A tempting LED, thanks to the slimmed-down price point

This flat-shaped bulb is a lighting aisle oddball, but we see value.

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Ry Crist
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Ry Crist

Senior Editor / Reviews - Appliances

Originally hailing from Troy, Ohio, Ry Crist is a text-based adventure connoisseur, a lover of terrible movies and an enthusiastic yet mediocre cook. A CNET editor since 2013, Ry's beats include smart home tech, lighting, appliances, and home networking.

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The lighting aisle's LED section is getting more and more crowded with legitimate values, so it shouldn't come as a surprise that manufacturers are looking for new ways to stand out. Enter the Philips SlimStyle, a low-cost LED that sets itself apart with an unusual, flattened design.

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7.8

Philips SlimStyle LED

The Good

The oddly-shaped Philips SlimStyle is a value-priced LED that serves as a respectable incandescent replacement. The flat design helps it manage heat better than other LEDs.

The Bad

The SlimStyle gives off an annoying buzz if you use it with a dimmer switch. Also, the three-year warranty isn't as good as the 10 years you get from the Cree LED, which costs just a dollar more.

The Bottom Line

For such a flat bulb, the SlimStyle is surprisingly well-rounded, making for a decent value at its price point.

This two-dimensional spin on modern, high efficiency lighting promises to replace the best aspects of a traditional incandescent while saving money on your monthly power bill. It also costs just $9, which converts roughly to AU$10, or £5 in the UK (Philips says it has no plans to expand the SlimStyle beyond North America at this time, but won't rule it out, either).

That price point is a dollar less than you'll spend for the well-reviewed Cree 60W Replacement LED , and significantly less than Philips' own standard 60W equivalent . Though it isn't a flawless light, or quite as cheap as the bargain LEDs that you'll find at Ikea , the accessible SlimStyle nonetheless offers excellent value, making it a good go-to bulb for common household lighting needs.

Check out Philips' svelte take on the LED (pictures)

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The decision to make a flat LED wasn't an arbitrary one. With a flat design, Philips was able to distribute the diodes around the bulb's perimeter, away from the heat at its base. This eliminates the need for aluminum heat sinks, which makes the bulb a lot lighter, and more importantly, a lot cheaper to produce.

The question is whether or not the flat design compromises the SlimStyle's ability to light like a typical light bulb. For the most part, the answer is no. With a light output of 800 lumens and a very accurate color temperature just under 2,700 K, it's a perfectly worthy replacement for a 60W incandescent. As for efficiency, the 25,000-hour lifespan and the 10.5W power draw put it right on par with other solid LED options. The color rendering score of 80 is in line with what you'd expect from most other LEDs, too.

Philips SlimStyle LEDCree 60W Replacement LEDPhilips 60W Equivalent LEDIkea Ledare LEDGE Energy Smart 60W Replacement LED
Lumens 800800830600800
Watts 10.59.5111011
Efficiency (lumens/watt) 76.1984.2175.456072.72
Color temperature 2,653 K2,669 K2,584 K2,632 K (frosted) 2,507 K (clear)2,562 K
Lifespan 25,000 hours25,000 hours25,000 hours25,000 hours15,000 hours
Color rendering index 8080818780
Weight 2.20 ounces3.70 ounces4.55 ounces4.10 ounces4.25 ounces
Warranty 3 years10 years5 yearsnone5 years
Price $9$10$15$5$10

The flat design does introduce a small problem with directionality, though. Like many of the LEDs available today, the SlimStyle promises omnidirectional light output, which means it claims to produce light evenly in all directions. This is mostly true -- except for the left and right sides of the bulb's profile, where you'll find dim spots. These get especially noticeable if you're using the SlimStyle under a lampshade.

Whether or not this is a deal breaker is up to you. Personally, I can't say that the dim spots would bother me all that much, as they don't ultimately affect how much light the SlimStyle puts out. I'd certainly notice them, though -- and that alone might be enough to get me to spend the extra buck on a Cree LED.

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Compared to the Cree 60W Replacement LED (left), the Philips SlimStyle has noticeable dim spots on each side of the bulb. Colin West McDonald/CNET

More likely to motivate my buying decision would be the difference in warranty between the two bulbs. The SlimStyle is covered for three years, compared to 10 years from Cree. That's a pretty substantial difference for such a small price increase, and probably well worth it for anyone who might doubt LED longevity claims.

Something else worth considering before settling on a bulb is whether or not you'll be using it with a dimmer switch. Most of the current LED offerings from major manufacturers claim dimmer compatibility and the SlimStyle is no exception, but as we learned in our recent round of tests, not all dimmable bulbs are created equal.

Which LEDs flicker the least? (pictures)

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In those tests, the SlimStyle showed the poorest performance. While it was compatible with every switch that we tested (even an older one designed for incandescents only), it also buzzed noticeably when used with each one, a result of electromagnetic interference in the bulb from the switch's dimming mechanism. The SlimStyle also showed a moderate amount of flicker, another common problem with dimmable lights.

After we published the results of those tests, Philips sent us some additional bulbs, telling us that the newest versions of the SlimStyle might perform better with dimmers than the release-day bulb we had tested. If there is a performance difference, it's a fractional one, and not one that we were able to detect. On our dimmer switches, the newer SlimStyles still buzzed, and they still showed a light amount of flicker, same as before.

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Colin West McDonald/CNET

All of this is to say that if you're buying a bulb for use with a dimmer switch, you'll want to go with something other than the SlimStyle. The best choice would actually be Philips' own standard 60W Equivalent LED , which aced the same dimmability tests that the SlimStyle flunked. At $15, that bulb costs a fair deal more than the SlimStyle, but I think it's worth it if you want smooth, dimmable light with no flicker or buzz.

Another bulb-buying consideration has to do with the heat generated by the circuitry inside. Just like with your phone or laptop, this heat will affect the bulb's performance, which is why LEDs put such a strong emphasis on thermal management.

When you first turn an LED on, there isn't any heat, so the power and light output that you see should be at something close to an optimal level. As the bulb heats up, generally over the course of about 30 minutes, the power output will diminish very slightly, until the bulb plateaus at what manufacturers call the "steady state."

Before you cry foul, keep in mind that the decline in light output is only barely noticeable, if at all. Also, LEDs don't get rated for brightness or efficiency until after they've hit their steady state, so you aren't getting shortchanged on specs.

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Over time, heat affects the SlimStyle noticeably less than other LEDs, which means it could be an especially good pick for use in enclosed fixtures. Ry Crist/CNET

With our spectrometer, we can track an LED's visible power output over time, then graph that steady state for ourselves, and we decided to do just that. The purple line in the graph above represents the Philips SlimStyle's power output over time, and as you can see, it does a great job, flatlining at around 92 percent of its initial brightness.

That's a higher steady state than any other bulb we've tested, and the only one we've found above 90 percent. Results like that suggest that heat doesn't affect the SlimStyle's performance as much as it does with other LEDs, which lends some credence to the bulb's unique design.

The practical takeaway from this is that the Philips SlimStyle might be an especially good choice for use in enclosed fixtures. Trap a bulb inside a fixture, and you're trapping it with the heat it produces, which can lower the steady state and potentially reduce the bulb's lifespan, too. A bulb like the SlimStyle, which manages heat particularly well, stands to suffer a lot less in settings like this than other LEDs.

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Colin West McDonald/CNET

Conclusion

At $9 each (or lower, if you live in a region that offers instant rebates for Energy Star-certified light bulbs), the Philips SlimStyle offers plenty of light bulb bang for your buck. You won't have any problems with its brightness or color temperature, and if you're switching over from incandescents, you certainly won't be complaining when your next power bill arrives.

That said, for a dollar more, the Cree 60W Replacement LED offers an uptick in efficiency, along with a 10-year warranty that's more than three times what you'll get for the SlimStyle. And for ultimate value, the $5 Ledare LEDs at Ikea are awfully tough to beat -- although their diminished brightness and lack of a warranty stop me from recommending them outright.

If you're looking for a bulb to use with a dimmer switch, you'll want to look elsewhere, as the SlimStyle tends to buzz quite a bit more than other LEDs whenever you dim down to 50 percent or lower. On the other hand, for enclosed fixtures -- globes, sconces, and so on -- the SlimStyle seems to be an ideal option.

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7.8

Philips SlimStyle LED

Score Breakdown

Design 8Value 9Performance 7