One of the greatest problems when it comes to produce and use energy is how much energy gets lost without achieving the desired work. Actually some very used electronic devices have low efficiencies and it seems that they are going to be utilized for a while. Extreme cases like some loudspeakers convert only 1% of the power in sound and the remainder ends being heat. Different setups of audio amplifiers use circuits with low efficiencies, specially at the output stage. This leads to big metal heat sinks and other time energy converted to temperature.
One of the most recurrent topics in efficiency appears in the use of linear regulators or switching mechanisms to send the energy in pulses. Linear regulators are simple and require even a single part in the circuit while switching mechanisms normally employ transformers, inductors, semiconductors increasing the complexity of the design. Doing the same for the user, a well-designed supply guarantees more efficiency and less energy wasted.
Today the energy for billions come with a price, both in terms of pollution or toxic waste and the economic side. It should force the population to think about the transcendence of wasting energy; also to have interest on demanding the most efficient technologies.
Now the use of tags it's common at the consumer level to inform about efficiency although as you could imagine it could be seen as another technique for the habitual business venture against the environment, still when the production price is equally low or it should be.
Not every company does it, in fact today there are examples of who doesn't and that's where the decision must be made at the purchase. The engineering field progresses with the search for 100% efficiency as if it were the lost ark. With a calculator in the hand, it's common to find products that look expensive but the saving in electricity restores the extra inversion and finally improves the total so it's the best move without doubts.
Our advice in this aspect is simply starting to be worried about who tries to make you wasting energy selling inefficient technologies. If it happens this materializes a bad market election and an open tap to environmental issues and higher electricity bills. Look for indications about efficiency in the specifications or in the product itself, asking someone of the informed staff is there's no clue.
After a bit any person learns the required information and has the necessary experience to proceed with more wisdom and responsibility.