Energy Efficiency Ratings Explained

When the EU introduced its energy efficiency labels in 2012, they seemed like a brilliant idea - stick an A-to-G rating on appliances, and consumers could instantly spot energy-efficient products. But there was a catch that no one quite anticipated: technology moves fast. Really fast.

As manufacturers developed increasingly efficient appliances, we started seeing ratings that looked more like a student desperately trying to earn extra credit: A+, A++, and even A+++. What started as a clear A-to-G scale had morphed into something that would make any UX designer cringe. The obvious question arose: why hadn't they started with 'M' or 'N' as the middle ground, leaving room for improvement in both directions?

In 2021, the EU decided to hit the reset button. But instead of creating an entirely new system (which might have made more sense), they opted to "rescale" the existing one. Think of it as trying to fix a wonky bookshelf by redistributing the books rather than buying a new shelf.

For example, what was once an A+++ fridge suddenly became a C or D under the new system. It's the same fridge, just as efficient as before, but wearing a different label. This created a fascinating scenario where manufacturers now had something to strive for again - the coveted 'A' rating became a nearly empty category, reserved for future innovations.

The impact on LED lighting was particularly dramatic. Under the old system, LED bulbs had clustered at the top of the scale, with most achieving A++ or A+++ ratings. The 2021 rescaling knocked these high-performing LEDs down to F or G ratings overnight - a change that puzzled many consumers. After all, how could the most energy-efficient lighting technology available end up at the bottom of the scale? The answer lies in the new system's forward-thinking approach: it leaves substantial headroom for future innovations in LED technology, anticipating that today's efficient bulbs might seem power-hungry compared to what's coming next.

The tables below show what the old and new label represents within the lighting industry.

An LED light bulb from the original 2012 system with an impressive 120 lumens per watt would have had an A++ rating, the new 2021 system downgrades the same product to an E rating. You're still getting exactly the same specifications, the brightness (measured in lumens) and energy consumption (measured in watts) is the same, only the energy rating has changed.

Having the same lumens and wattage means that the lumens per watts is still the same. Often shown as lm/W, this is the common variable between light production and energy consumption. This can be calculated by divided the lumens by the wattage. For example an LED light bulb with a light output of 1521 lumens and 11.2W energy consumption has a lumens per watt of 135 lm/W. While this is a very energy efficient LED, is only D rated on the latest system.

Efficacy

The word efficacy is used to describe energy efficient within the lighting industry as there are other variables to consider when making calculations. Such as the total wattage, which might include an LED driver, the light output ratio, which tells you if you lose any light within the fitting, for example a 50W halogen used to lose 10% of its light in its reflector.

The way energy ratings are calculated for any lighting product is to determine the efficacy. Calculating the lumens per watt is a good way of comparing different types of lighting products. It tells you how many lumens you get for every 1 watt of energy consumption.

Efficacy Example

For example a 5W LED GU10 with a 520 lumen output has an efficacy of 104 lumens per watt. This would put it in the F rating category , when it used to A+ rated.

The Most Efficacious Lights

This new system has come very early for GU10 LEDs and integrated LED downlights. The most energy efficient GU10 LED is the Philips 2.1W GU10. With a light output of 375 lumens, it appears to have an efficacy of 178 lumens per watt, on paper it looks like it should be classed as C rated but Philips (now Signify) have explained that GU10 lamps and other directional lamps are calculated differently to other light bulbs...

The way EEL(Energy Efficiency Label) is calculated for directional light is different than that of a bulb.

Taking the index of 1.176, you will get a Class A grade, it is the same case for future A class GU10, and also the same for other competitors.

The calculation is: 1.176 X 178 = 209lm/W

We anticipate a new generation of integrated LED downlights to surpass these in 2025 as this is the only next logical step for LED lighting technology, especially in a more energy conscientious age.

Summary

Don't spend too much time looking for LEDs with a certain energy rating as the system still needs some work. You might have an LED that is just a few lumens short of being A rated, this minimal difference isn't going to make much effect to your lighting results and won't reduce your energy bills by too much. Just calculate the lumens per watt and you'll be able to compare it to another lighting product.