In my home, I have some halogen spot lights, which have an energy efficiency rating of 'C':

Osram halogen Decostar 51 standardGU5.3 bulbEnergy efficiency rating C

I would like to replace them with more efficient LED bulbs, but looking on the Philips website, they claim their bulbs are rated 'F'!

LEDspot VLE GU5.3 MR16 7W 830 36D
LEDspot VLE GU5.3 MR16 7W 830 24D

Why would a 50W bulb be rated better than a 7W equivalent?

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    \$\begingroup\$ Note that the links to not point to the Philips website but to a retailer, and possibly not the most recent version of those bulbs. Similar (and more recent) bulbs on the Philips website do also have ratings of F or even G, though. \$\endgroup\$
    – jcaron
    Commented Jan 4, 2022 at 11:59

3 Answers 3


EU energy ratings get re-done regularly; a rating indicates placement in the field of competitors at the time of rating.

Things that were A a couple years ago might now be G; hence, you need to evaluate things with comparable tests. Since new halogen reflector lamps haven't been into the market in the last decade, these ratings are simply outdated.

Energy label Standardized Energy label. Note (VII) needs to be the same for different labels to be comparable. The currently valid regulation, as per the consolidated regulation linked to below, is 2019/2015 (state of 2021-09-01)

As far as I could figure out quickly, the valid energy efficiency classes since 2019 are:

Energy efficiency class Total mains efficacy ηTM (lm/W)
A 210 ≤ ηTM
B 185 ≤ ηTM < 210
C 160 ≤ ηTM < 185
D 135 ≤ ηTM < 160
E 110 ≤ ηTM < 135
F 85 ≤ ηTM < 110
G ηTM < 85

And halogen incandescent lamps achieve of only up to 24 lm/W, so they can't be any better than G.

Source: EU Commission Delegated Regulation

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    \$\begingroup\$ Not quite sure where the downvote comes from, if the person downvoting could comment, I might improve my answer :) \$\endgroup\$ Commented Jan 2, 2022 at 22:08
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    \$\begingroup\$ Upvote added - to balance AND deserved :-) \$\endgroup\$
    – Russell McMahon
    Commented Jan 3, 2022 at 8:47
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    \$\begingroup\$ Good answer. Don't worry about the odd downvote. Look at great YouTube videos, they get hundreds of thousands of +1s and always about 2% of that as -1s. There's a lot of weird folk on the internet, and accidental clicks and fat fingers. You can never please everyone. \$\endgroup\$
    – Dan
    Commented Jan 3, 2022 at 14:42
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    \$\begingroup\$ @DouglasLeeder Looks correct to me? Category A produces more than 210 lumen per watt. \$\endgroup\$
    – gerrit
    Commented Jan 4, 2022 at 8:54
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    \$\begingroup\$ Note that it's pretty clever to regulate so that right now, it's hard to come into the top tier; otherwise, you'd not be offering a competitive advantage to innovate for efficacy. \$\endgroup\$ Commented Jan 5, 2022 at 10:24

The old ratings were designed for incandescents, so all the modern LED bulbs were getting absurd ratings like A+++, so they just changed the scale to make it harder to get the A rating. Basically C is the new A++. So you can't compare the old scale and the new scale.

Of course, this means the previous labels on your fixtures that said "do not use bulb below class C" no longer mean anything. But these labels were meant to prevent you from using incandescent bulbs in fixtures made of plastic that wouldn't tolerate the heat, and there are no more incandescent bulbs, so who cares.

The useful thing about this regulation is they made it mandatory to specify the light output in lumens. So you can look at how many lumens it outputs, look at the power, divide, and you get the efficacy in lumen/W.

Now you may ask, why is the efficacy in lumen/Watt not what is printed on the box instead of useless "ABC" ratings? Well, it's brought to you by the same bureaucrats that give my gas-guzzling V6 a better pollution rating than my high mpg diesel, lol.

Note luminous efficacy of LED lightbulbs is not relevant unless you have a very large number of them. If you upgrade a bulb from a 13lm/W 60W incandescent to a 100lm/W 8W LED, both output about 800 lumen, and you save 52 Watts, and it does add up. But if you upgrade that 100lm/W 8W LED to a 200lm/W 4W one, you only save 4 watts.

IMO it's better to focus on quality: no flicker first, then higher color rendering bulbs which have a bit lower efficacy, but they are absolutely worth the extra watt. If you like the color rendition of halogens, the 3000K CRI90 spots from Osram are a nice match.

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    \$\begingroup\$ IMO, lumens per Watt is not everything. Comparing an incandescent bulb with a bad LED with bad CRI (at the same lumens), I think it is easier to see stuff with the incandescent bulk, contrasts are more natural etc. so the better the CRI, the less lumens I need for the same perceived contrast level. So I agree, that CRI is more important than pure lm/W. PS: I don't want to lobby incandescent bulbs, but I advocate good LEDs with high CRI. There are now bulbs with advertised CRI way over 90 \$\endgroup\$
    – tobalt
    Commented Jan 3, 2022 at 8:38
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    \$\begingroup\$ @tobalt absolutely agree, there are nice inexpensive bulbs in 90CRI, and really good ones (like ExpertColor with CRI97), and we're finally getting out of the yellow overdose as 3000K becomes much easier to find. The GU10 are even better than halogens, I certainly don't miss them. \$\endgroup\$
    – bobflux
    Commented Jan 3, 2022 at 10:42
  • \$\begingroup\$ Incandescents may not be commonly sold anymore, but they're definitely still around. \$\endgroup\$
    – Vikki
    Commented Jan 4, 2022 at 4:53
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    \$\begingroup\$ To address your aside, it's because burning diesel produces a lot worse pollution than burning petrol. To the extent that there was massive industry fraud attempting to hide it that was uncovered in 2015. \$\endgroup\$
    – OrangeDog
    Commented Jan 4, 2022 at 16:02
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    \$\begingroup\$ @tobalt ... which is why I stuck with real fluorescent... every shop has 90 CRI tubes at non-premium prices. \$\endgroup\$ Commented Jan 4, 2022 at 16:36

To add to Marcus's answer, the luminous efficiency of that bulb is 78 lm/watt at a CRI of 80-90. In an absolute sense that is fairly good, reaching something like 20% of the theoretical perfect efficiency for a white phosphor LED at that CRI value, which is far better than an incandescent. However, LEDs can be extremely efficient, and diodes in that CRI class of about 200 lm/watt are available. Thus in a relative sense, those lights are quite poor, using about 2.5x more energy then is required for that amount of light.

Think carefully about how often you will use the lights and the absolute amount of energy savings. A 6w light used an hour a day will not save a large amount of electricity if you double the efficiency. A 50w flood light used 12 hours a night will benefit a lot more from higher efficiency.

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    \$\begingroup\$ Thanks, this is useful to know. Do you have a link to such a light? I have not been able to find one. \$\endgroup\$ Commented Jan 3, 2022 at 21:38
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    \$\begingroup\$ @Rocketmagnet google "dubai led". The Dubai government set that as the minimum standard for any light sold, et voilà it happened. \$\endgroup\$ Commented Jan 4, 2022 at 16:39

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