Puzzling energy rating

[Roddy Young]

Can anyone explain why my 2 watt christmas tree lights only have a G rating?

 

[EFLImpudence]

Because they are a waste of 2W. ???

 

[Murdochcat]

Because the grading system is dumb

 

[Harry Bloomfield]

Can anyone explain why my 2 watt christmas tree lights only have a G rating?

Probably, the G means they have never bothered to have them rated, why would you? They don't get much use, except for a few weeks, during which who cares about economy.

 

[nero44]

I think they are rolling out these changes to all electrical appliances.

I think it makes sense for larger more complex appliances (white goods+TVs etc), maybe not so much for a string of christmas lights... But then common sense should apply and and you should not worry about it.

For more complex appliances, yeah I see how developments in technology will make old standards outdated and incentives companies to tweak a bit more to make things more efficient.

 

[endecotp]

Because the ratio of electrical power in to visible light out falls into the range of values defined as band G.

Considering the way that some houses are adorned with thousands of these lights, sometimes for months, I think it's worthwhile to rate them.

"Why I light up my garden for more than half the year" : https://www.bbc.co.uk/news/articles/cdj8md80mkwo

"Man heats home with over 4000 Christmas lights" : https://www.bbc.co.uk/news/av/uk-25002201

 

[ericmark]

I looked at the tumble drier, basic three types, vented, and two condenser types, air cooled and refrigeration type, there is water cooled, but normally only used as part of a washing machine.

So to compare, we need to look at energy used to dry a set amount of clothing within a set time. The latter is the problem, if it takes the heat pump 2.5 hours, then we need to find a vented and air cooled which also take 2.5 hours.

But the air cooled all take around 1 hour, so near impossible to compare them, the vented there were versions which took 1.5 hours and 8 hours although not still made, as far as I know. To use 2 x 1 kW elements in a vented drier is still done, and this results in 1.5 hours drying time, so we have best heat pump, then vented, and worse air cooled, but the reason is down to drying time, not the efficacy of the system.

With LED lights, we also have a number of factors.
1) To stop lights remaining on dim, when switched off, due to capacitive or inductive linking either the lamps need to be DC or they need a bleed resistor.
2) To convert from voltage to current dependent, we can either use an electronic driver, or a simple resistor, the latter uses ¼ of the energy supplied, so that will reduce efficacy a lot.
3) In the main, we want to start at 12 volts, again it is how we get the 12 volt to start with.

Basically, the less power used, the larger percentage of the power is waisted.

But this does not include getting the light to the correct area, here I was trying to reflect the light down onto the drive with silver foil, I could use the same foil inverted, or use a filament bulb, or use the old folded fluorescent tube, or a integral lamp with all the LED's in the top, so light starts out being directed down. I want the floor illuminated, not the trees, and I only need enough to see my way down the drive.

So yet another option is loads of little lights, following the wall up to the road, the latter in spite of being very inefficient light output wise, they are super efficient watts used to see the way to the front door.

But if the same lights are used to just decorate, then 100% loss, so how can anyone say how efficient. All the manufacturer can say is lumen per watt, rest is down to how used.