In our continued search to find the ideal GU10 bulb, we came across the Philips “Warm Glow” 50w replacement.  Will this finally be a suitable replacement to hot halogen equivalent bulbs?

Let’s find out.

ADVERTISED SPECS

• Connector:  GU10 (120v)
• Brightness:  400 lumens(~50w equivalent)
• Consumption:  5 watts
• Efficiency:  80 lumens per watt
• CCT:  2,200K – 2,700k (“Soft White Light”)
• CRI:  83 (per Energy Star certification)
• Dimmable:  Yes
• Output Width: 35 degrees (per Energy Star certification)
• Make / Model:  Philips 9290011565
• Energy Star:  Yes (but not indicated on Retail Packaging)
• Warranty: 5 year replacement

SPECS EXPLAINED

According to the listed specifications this bulb generally falls within a normal range for consumer bulbs.  Efficiency of 80 lumens per watt for a compact GU10 bulb is on the more efficient side of the normal range.  Interestingly this bulb is listed as an Energy Star product but does not include the Energy Star logo on the packaging.  The absence of the Energy Star logo may be attributed to the lengthy test procedures.  In any event, the certification testing indicates a light output width of 35 degrees (considerably narrower than the 40 degree width typical on halogen bulbs) and a CRI of 83, among other measurements.

The Correlated Color Temperature (“CCT”) of 2,220-2,700 is supposed to closely resemble warmer  incandescent / halogen bulbs.  This is good.

Warranty is above average at five years replacement coverage.  This suggests that Philips is confident in the durability of this bulb.

Like most bulbs, there are no advertised specs on flicker.  Let’s find out how it might suit those most sensitive.

FLICKER AND COLOR

Unfortunately, our hunt for a GU10 bulb with no measurable flicker does not come to a close today.  We detected flicker depth of ~30% at a frequency of 120Hz.  In other words, this bulb pulses rapidly between around 70% brightness and 100% brightness 120 times each second.  While flicker at such a high frequency is invisible, it may contribute to symptoms of those most sensitive.

Advertised color temperature is between 2,200K and 2,700K, depending on activation of a dimmer switch.  While we didn’t measure the dimming capabilities of the bulb, we did measure a CCT of 2,792K at full brightness, which is slightly cooler than what was advertised but perhaps within a range of error.

The Color Rendering Index (“CRI”) isn’t advertised on the  retail packaging, but we found Energy Star to have measured a CRI of 83.  Our own measurement shows this bulb scores an 82.6.  A mediocre result.

Subjectively the light appeared a bit ‘off’.  Upon a closer look, we found it performed poorly in the very important R9 CRI value, scoring just 16.9 out of 100, whereas a good result would achieve a score better than 60.  The R9 CRI indicates whether or not shades of red illuminated by this light will be rendered accurately.  Shades of red are everywhere, from skin tone to wood cabinets, to meat you might cook for dinner.

OTHER CONSIDERATIONS

Given the flicker depth of ~30% we don’t recommend this bulb for those most sensitive, even despite the warmer CCT of 2200-2700K.  Generally speaking, the poor score of the R9 CRI precludes this bulb from being recommended to anyone, regardless of light sensitivity.

We generally look forward to reviewing Philips products, but were disappointed with the performance of this bulb.