energy saving comparison LEDs

[jw52]

Can anybody give an opinion on the cost saving in energy of four LED spots built in compared to a bar with four LED GU bulbs? Obviously the former runs on a transformer and the latter on mains. How much real difference would there be in energy terms?

 

[mfarrow]

How much real difference would there be in energy terms?

Over a set time period, that would depend purely on the Wattage rating of lamps. A strip of 4x6W LEDs (24W) will consume less than 4x5W GU10s (20W).

 

[efficiencyman]

Why change 12 volt to 230v GU10 ? is the existing wiring suitable to do that ?. 4, 5, 7w are coming out now as bright as 50w halogen with good colour temp in MR16, may need to change driver. Save about 90% on Leccy bills. I bought some more a few days ago for a fiver --- brilliant !

 

[ericmark]

Can anybody give an opinion on the cost saving in energy of four LED spots built in compared to a bar with four LED GU bulbs?

GU10 are spots so not really sure about question!

Obviously the former runs on a transformer and the latter on mains. How much real difference would there be in energy terms?

Why should the former run on a transformer? Yes power supplies are used to power LED lamps not often simple transformers though. Some current limiting device is clearly required with all LED lamps be it simple voltage and a resistor or full current limiting and it does not really matter if built into lamps or separate it will still exist some where.

LED lamps should have a very long life and so to my mind changing the current limiter with the lamp makes a lot of sense as you are then assured the current limiter is not going to fail taking the lamp with it.

Capacitors of electrolytic type have a limited life and most power supplies use them so I would use GU10 type and so not have to ever replace the power supply.

I do have 4 lamps that do use a true transformer (not switch mode power supply) and I swapped quite a few 50mm spot lamps for LED which includes this set of 4. Of all the LED lamps fitted this set of 4 are the only ones to have had failures. OK were very cheap lamps but so were the others. So I would as a result tend to go for GU10 not 12 volt if starting from scratch with the exception maybe of the bathroom.

 

[Taylortwocities]

Ignore the wattage information.

These days lamps are specified in lumens = brightness. Comparing lamps by watts is pointless as it is a measurement of power in to the lamp, not the light output.

More infor here http://www.energystar.gov/index.cfm?c=cfls.pr_cfls_lumens

 

[ericmark]

Why change 12 volt to 230v GU10 ?

In the main because we don't use transformers but switch mode power supplies to power 12 volt lighting. There are a few problems where originally for tungsten lamps often the minimum current rating will stop you being able to use them and second is GU10 is normally easier to change bulbs with at the bayonet holds the bulb in place with out any extra rings or clips.

is the existing wiring suitable to do that ?.

Good point here however if not still means comparing cost of power supply change to wiring change clearly we can't do that.

4, 5, 7w are coming out now as bright as 50w halogen with good colour temp in MR16, may need to change driver. Save about 90% on Leccy bills. I bought some more a few days ago for a fiver --- brilliant !

Hang on question was about extra low voltage LED compared with low voltage LED either way going for saving in using LED I think it unlikely that there is any difference in efficiency between them. Even if there is a difference it will be so small it would be hard to measure. So comparing having holder, lamp and power supply v holder and lamp. Why then get a power supply? Only reason I can see for extra low voltage is for use in a bathroom.

Note:- extra low voltage 0 - 50 vac and low voltage 50 - 1000 vac so 12 volt is not low voltage it's extra low voltage. 230 vac is low voltage.

 

[ericmark]

These days lamps are specified in lumens = brightness.

This is the problem it's not brightness but light output and the brighter the lamp the more distance the light will travel so swap a tungsten bulb for CFL then directly under the lamp just as much light if same lumens, but in corners of the room that's not the case.

The LED lamp does tend to be rather bright so yes these do seem to reach corners of the room but also have a problem with being rather a directional light. Swapping 60 degree tungsten lamps for 15 degree LED lamps is clearly going to cause a problem.

The GU10 spot is as one would expect a spot light and mounting lamps in the ceiling to illuminate a picture these work well. Same where extra light is required on a work surface. However to get general light the beam needs reflecting off a light surface so yes with light walls and ceiling you can bounce the light and so light whole room. However floors tend to be darker and so do not reflect the light very well so if the spots are aimed at the floor then light is absorbed and it looks like a planetarium.

It is not just a case of this room needs x lumens would be nice if it were. Fit two LED GU10 11w spots and compare to two 2D 11W ceiling lamps and often the 2D will do a better job even though they are not as efficient and give out less lumens.

Much depends on the room I have myself made a big mistake when swapping 6 foot florescent lamps for metal halide low bay lamps where the roof was too low. Worked great when roof was 20 foot high failure with roof 10 foot high.

So take both watt and lumen output as guide it's also dependent on type of light and if it suits that room.

 

[efficiencyman]

I have also been impressed with the output of these new 650 cd LED`s using the new TCH technology http://www.ebay.co.uk/itm/221303199349?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 from Megaman.
There are so many new types coming on to the market, almost on a weekly basis now from so many makers -- very exciting developments. Point taken about wattage but users still want to know the consumption, lumens, Candelas, Beam angle spread, colour range, cap type, voltage, life span, comparison of equivalent replacement wattage, etc. etc.
The motive for changing will still be the long term savings, the needed amount of light for less consumption (i.e. less watts used ) LED`s use about 82% to 92% less energy than tungsten Halogen.

 

[big-all]

thats interesting
at 270 lumens its about 1/5 the output off a 100w bulb at 1300 lumens so 21w but they replace a 35w

by my reckoning i always say a ratio off 9 to 1 as a rough guide so 7w would be a 63w equivalent
but for 7 w i would expect more like 350-400lm for a globe ball replacement

 

[ericmark]

I would agree however question was 12v LED v 230v LED I personally can't see much between them and I wonder if there is an error in the question?

 

[Taylortwocities]

Big-all. If you take the trouble to look at the link I posted (above)

More infor here http://www.energystar.gov/index.cfm?c=cfls.pr_cfls_lumens[/QUOTE]

You will find a handy table of
Incandescent bulbs (watts)
Minimum light output (lumens)
and the equivalent consumption in watts of typical "energy star" lamps.

That will save you too much wasted time on your calculator

 

[JohnW2]

A strip of 4x6W LEDs (24W) will consume less than 4x5W GU10s (20W).

Have the meaning (at least, relative sizes) of 24W and 20W changed whilst I wasn't looking ?

Kind Regards, John