LED downlighting ( energy-efficient)

Yes, same happened to fridges/freezers/washing machines etc, stuff that was A+++ dropped way down but was still the same machine, some EU change I believe

March 2023 was the last date allowed for the sale of goods marked with the old labels.

So if you had these 10 downlights at this wattage and you had them on 6 hours a night, at the height of winter, you'd use 10*6*4.7 = 282 watts. If you're paying say €0.40 for a kwh of electricity, the lights have cost you €0.1128 (just over 11 cent) for that night. 

So this is all relative I.e. if you could get downlighters at say 2.3w, which is just over 50% less, you would use 10*6*2.3 = 138 watts which, at the same €0.40 per kwh would cost you €0.0552 (5 and a 1/2 cent). So obviously it accumulates but not sure I'd be in a rush to invest in early version of the next generation if the cost is way more as not sure the savings justify it....

If. It all depends on the If. :-)

For my installation, those ten bulbs will light two rooms independently, and they're the "oooohhhhh, soooo bright, turn them off" lights, so they'll probably be on for about 6 hours a year, not per month. The bulbs supposedly give out 450 lumens each, so the installation is sized to flood the area with three times the recommended illumination for the space (I have my reasons).

Like with every energy calculation, you can plug various figures into various formulae and get just about any result you want but the simplest way to reduce it is not to use it in the first place, which is the intention here. Each of those rooms will have two other light sources ("mood" and "spot") that'll account for the month-to-month cost, so I was quite happy not to spend three times the amount on just-in-case fixtures, especially as it was literally a case of the "wrong" packaging. The whole kit (cabling, connectors, housing and bulbs - which, of course, can be changed in an instant) cost less than most single wall lights, bulb not included ... and a third of the price of the exact same product now on the shelves in a new box.

You've also ignored the lumens-per-watt parameter in your alternate scenario - which is what gives any bulb its energy rating - and neither of us has touched on the colour temperature or angle of spread. Depending on how the downlighters are arranged, you might find that you need ten of your 2.3W bulbs on at the same time to give enough light while I can get by with just three. It all depends on the Ifs ...

Fair enough. But the energy usage is a function of the wattage requirement. The lumens might determine how many you need on - but they are likely to be wired I series so you won't have independent control - unless perhaps they are a smart bulb. Agree with the other poster - the saving dropping from 60w and 100w as standard bulbs to bulbs of 3w to 5w energy usage which also last for far longer has been significant. In all honesty, the saving in dropping from a 4.7w to a potential 2.5w is not as substantial.

Mad to think that something like 90% of the energy usage of a 100w bulb was in generating heat....

10-10-20 was on the money here

European_Union_energy_label

From 1 September 2021[12]

Every label of light sources, including light bulbs (halogen, compact fluorescent, etc.) or LED modules/lamps, contains the following information:

• the energy efficiency category from A to G
• the electricity consumption of the lamp in kWh per 1000 hours

vs

Until 31 August 2021

Energy classes of light bulbs in terms of luminous flux and power consumption (until 31 August 2021)

Every label of light bulbs and tubes (including incandescent light bulbs, fluorescent lamps, LED lamps) contains the following information:

• the energy efficiency category from A to G
• the luminous flux of the bulb in lumens
• the electricity consumption of the lamp in watts
• the average life length in hours

which explains why when looking to buy a work light, no sign of lumens/watts/temperature

what a regressive step

The new A to G graph will not copy, but the values are in total mains efficacy, not efficiency as per above

Efficacy is getting things done. It is the ability to produce a desired amount of the desired effect, or success in achieving a given goal. Efficiency is doing things in the most economical way

ao a bit of clusterfcuk

efficacy meaning

Agreed. Our dishwasher was bought when it was dual code I think. Something like A on one scale; F on the other. And you're right. The scale is one thing but understanding your usage, the power consumption, the initial outlay and payback of going for much more expensive new A versus F means you are better informed and better able to make a decision.