LED performance, the gap between advertised and real luminous flux (2)

In this previous post we have written about how the brightness (luminous flux) of a LED lamp varies with the operating temperature and have said that some producers only advertise the performance at an optimal, lab temperature, of 25 ºC.

We have also shown that the savings promised by LED technology are real only for high performance LEDs.

Now we will talk about another, more serious, aspect about the advertised performance of LED lamps: false advertised brightness.

The brightness (luminous flux) of a light source is impossible to measure at home. One needs specialized measurement equipment and knowledge to measure the luminous flux and some producers take advantage of this aspect to claim their LED lamp has a lot more lumens than in reality.

Lets look at the specs of the LED bulb below:

The producer of this particular light bulb claims his "High Brightness 5W LED Bulb" has a impressive 550 lumens. But is it true? How can we find out the answer without a lab to do the measurements?

Fairly easy, we use comparison and common sense.

For comparison we go to the website of a known brand, in the case of LED bulbs this can be: Samsung, Philips, Osram, Toshiba and we look at the specifications of a LED bulb with similar wattage:

 The Samsung LED bulb above has 490 lumens for 6.5 Watts and we can find products with similar specifications at the other brands too. Thus, our common sense tells us that the little known producer that claims his bulb has 5 Watts and 550 lumens is not telling the truth.

 The savings promised by LEDs occur only if the producer gives honest information about his product`s performance.