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Comparing Lights

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Started 3 years ago by MarkT
Latest reply from rockabye

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MarkT
Member

I'm a bit confused but how do you compare the light output/brightness of the various types of lights that are on the market.

Incandescent lights are measured in Watts
CFL lights are measured in Watts and include an equivalent Incandescent wattage so you can know the light output
Fluorescent tubes are measured in Watts
Halogen lights are measured in Watts
LED lights are measured in Lumens

I have tried to find out how much Lumens a 50watt Halogen light is rated to so that I can compared the LED lights to Halogen but I can

Posted Friday 21 Nov 2008 @ 1:06:40 pm from IP #
ghostgum
Member

Lumens is a measure of the total light output.
Watts is a measure of the electrical power input.

The figure of interest is "Luminous Efficacy" or lumens/watt.
http://en.wikipedia.org/wiki/Luminous_efficacy

It is difficult to find the lumens/watt for a halogen lamp. They usually specify the light intensity at the centre of the beam (using the related Candela or Lux)

An Osram 50W IRC Halogen, which is slightly more efficient than regular halogens, has 1250lm output (25 lumens/watt). They claim this is equivalent to a regular 65W Halogen (19 lumens/watt).
http://www.osram.com.au/_regional_APAC/pdf/Consumer/General_Lighting/IRC_brochure_APR_lowres.pdf
These efficiency figures are from the Halostar light without reflector.

In comparison,

Cree XR-E LEDs (P4 bin) at 350mA/3.3V=1.16W is about 92 lumens (80 lumens/watt)
http://www.cree.com/products/pdf/XLamp7090XR-E.pdf
Compact fluorescent (Osram 18W Duluxstar Mini Twist) is 1200lm (67 lumens/watt)
http://www.osram.com.au/_global/pdf/Professional/General_Lighting/Compact_fluorescent_lamps/102SO18GB_DULUXSTAR_Mini_Twist.pdf
T5 fluorescent tube is about 90 lumens/watt.

LED lights are similar in efficiency to fluorescent.
The fluorescent light output will vary between manufacturers, and also between different technologies. The 840 phosphor is more efficient than the 740 phosphor, even though they are both cool white.
Long T5 fluorescent tubes are more efficient than compact fluorescent.
T5 fluorescent tubes are more efficient than the older T8 (1 inch diameter) tubes.
The radiation pattern of compact fluorescent lights vary depending on the shape of the tube. Many are brighter from the side than the end.

Posted Monday 24 Nov 2008 @ 2:41:44 am from IP #
Benny
Member

Thats a great summary Ghostgum - everyone should be aware of these figures/methods.

I can understand your confusion with regard to LED's MarkT - sadly current sellers and maufacturers are just trying to sell them because they are "very low power" (2-3W) without specifying how bright they are. A few admit that at 2-3W they are only suitable replacements for 20W halogens as spot/desk lights. As Ghost gum says LED's are about the same efficiency as CFL's at present, especially when they get hot and try to give high output per LED. So to compare an LED to a CFL, just compare the Wattage - a 2-3W LED will be about the same brightness as a 2-3W CFL - which hardly anyone uses - at least for room lighting.
Still LED technology is still developing and I see a few places are starting to offer 10 and even 15W LED fittings - enough to do a whole room - although like early CFL's they are expensive at $30-40 and even more. If you think the "no mercury" and very long life are advantages though - go LED !

Posted Tuesday 25 Nov 2008 @ 2:37:42 am from IP #
ghostgum
Member

A few other opinions about LED vs Fluorescent.

If you want a bright beam, use LED. It's much easier to get a narrow beam from a small LED than from the much larger fluorescent tube. (I'm ignoring HID lights here). LEDs are good for bike lights, hand torches and spot lights.

If you want general illumination, use fluorescent.

If you need a dimmable light, use LED. These get more efficient when dimmed (because they run cooler). Some fluorescent lights can be dimmed, but like incandescent are less efficient when dimmed.

If you need a light that turns on and off quickly, use LED.

A bright LED light isn't small. It's got a big heat sink attached to it. I think LED room lighting should be based on integrated LED and fitting, with the fitting being designed as the heat sink. When done properly, it won't look like a heat sink. Have a look at Lance Turner's article in a recent ReNew magazine about his LED room light.

If you want lots of light for less cost, use fluorescent.

Posted Monday 1 Dec 2008 @ 12:41:44 am from IP #
photomac
Member

You guys are brilliant!
I am loving the colour tone the LEDs put out.
I have found that Ikea are selling strip LEDs in a hard "D" shape strip. Four strips to the meter. There are 4 x 250mm strips, that can be connected directly to each other or via mini 50mm cables. The transformer has four outlets but rated to only supply 6 strips. There are 4 strips, one transformer, four mini cables and four long supply cables. They are $69 per pack. Compare this to online LED suppliers at $120 per meter raw - no housing, no transformer, no switch. I have been modifying the cable lengths to insert the strips as bookshelf lights and desk lighting and shelf lighting. I recomend these units. Gets costly after a while but nice to know that a desk running 2400mm lit by 4.2W is good to read by! But I do need to put a power meter on this to see if draw is rated as to what is printed on the devices.

Posted Thursday 4 Dec 2008 @ 9:03:44 am from IP #
ericoppel
Member

Has anyone here had a look at what's available overseas in LED lighting such as downlight replacements?
I am tired of being ripped off by suppliers here in Australia who market LED lighting as some sort of specialised premium product at ridiculously inflated prices. It's a bit like what happens here with being charged super high prices for organic produce. All this stuff should be treated as what it really is..... normal everyday necessities at normal everyday prices.
The lighting suppliers here try to then justify it by saying that their products are higher quality or standard etc etc, but generally that is not the case, it's just good old fashioned profiteering. This can be seen by anyone when travelling overseas where you can see LED products of very high quality and meeting the highest electrical standards and all at very affordable prices nowadays. Sadly our Aussie entrepreneurs, like our governments are keeping us back in the dark ages by outdated ideas and their greedy practices making it unaffordable for most of us to convert our entire home lighting to LED.
I would be interested to hear from anyone who has had the sense to buy from Asian manufacturers, maybe like those found on Alibaba.com or elsewhere who often sell in small quantities direct to the public online?
What lights did you buy and from which manufacturer?
It's time we stopped putting up with the BS and got on with being more energy efficient as a nation. The government is obviously incompetent to do it, the importers are only interested in profiteering, so it looks like it's up to individuals to say enough is enough and simply do it without them both!

Posted Friday 23 Oct 2009 @ 11:19:11 pm from IP #
dymonite69
Member

There are several considerations when choosing a lighting system:

Lumens - total light output
Colour rendition - not as good with fluorescents and CFLs (but improving)
Beam spread (measured as beam angle or centre beam candle power - CBCP)

Lux measures the actual light falling on a surface. You might get more lux (a concentrated pool of light) from a luminaire with low lumens and narrow beam angle than one with high lumen and wide beam.

If you just changed all your incandescents to LEDS, you may find that the lighting conditions will change even if they represent the same lumen output.

Good lighting schemes depend on a combination of general lighting (wide beam, suspended lamps) and accent/task lighting (narrow beam, surface or recessed lamps)

To use LEDS to provide general lighting would require more light sources per unit area than would otherwise by achieved by alternative luminaires.

Here is a study where they tried to model the effects of using LED only for a office setting and found the configuration would consume more energy than a conventional layout.

http://www.lrc.rpi.edu/programs/solidstate/pdf/SPIE5187-43_Gu.pdf

In terms of luminous efficiency LEDS are on par with straight fluoros and only slightly better than CFLS.

Roughly 60W incandescent = 50W halogen = 12-15W CFL = 10W Straight fluoro = 10W LED

But don't forget about beam angle!

Posted Friday 23 Oct 2009 @ 11:52:54 pm from IP #
ericoppel
Member

Some good info there, but like most info and opinions on LEDS much of it is very out of date. 2004 is like the dark ages compared to what LEDS are capable of doing in 2009. LED technology is improving almost daily now and they are certainly able to provide good light output as well as colour and beam angles compared to those days.
Nowadays with the right info and some creativity lots can be achieved! It's exciting times for lighting!

Posted Saturday 24 Oct 2009 @ 12:11:38 am from IP #
dymonite69
Member

I would still stay the usual offering isn't going to have me switch over from fluoro technology (even if I were to ignore the additional costs). Energy efficient lighting involves more than a lumen/watt analysis. For instance recessed lighting is an inefficient method of providing general lighting and I am still doubtful about using LEDS in a pendant.

Posted Saturday 24 Oct 2009 @ 1:17:19 am from IP #
ericoppel
Member

True, recessed lighting has always been a very inefficient way of providing general lighting and really only became popular for it's aesthetics more than anything else.

For general lighting in most smaller rooms an ordinary centrally located flouro or a bayonet fitting with a CFL is pretty hard to beat for bang for buck value.

LEDS are now so bright that they are already being used for car headlights so I think with the right configuration of LED's, direction and reflector design in the fitting I'm sure they will soon be commonplace in most households.

I have a 16 LED torch which I bought for $7 which is almost as bright as my old 35w 6v halogen spotlight and runs for hours longer on a standard lantern battery. It still amazes me every time I use it!

Posted Saturday 24 Oct 2009 @ 2:07:26 am from IP #
dymonite69
Member

I am not worried about the brightness of LEDs, I have a few torches that run on them. However the beam angle for car headlight is not so useful for a household. If the spot is too intense, it just causes glare. I still see LEDs as more suitable for things like lighting desks and benches or splashing a light on a wall hanging.

Posted Saturday 24 Oct 2009 @ 7:26:05 am from IP #
ericoppel
Member

It doesn't take Einstein to design a LED with suitable lens/ reflector to produce whatever beam angle you want. It is simple optics. All that stuff was figured out years ago in the days of candles and oil lamps.

Even the recessed downlight styles are nowadays available with angles such as 100 degrees which is far more than the archaic halogen globes they replace. Outputs of these of around 70-91 lumens/watt are not unusual, so a 13 watt lamp for example would give a quite repectable 910 - 1180 lumens depending on which colour temperature you choose from 3000K to 5300K. Non recessed lamps can of course be produced with anything up to 360 angle.

I see you are a sceptic but I hope you will soon see the light! Pun intended.

Posted Saturday 24 Oct 2009 @ 7:43:02 am from IP #
ericoppel
Member

Forgot to mention the average halogen downlight has only about a 60 degree angle.

Posted Saturday 24 Oct 2009 @ 7:44:23 am from IP #
dymonite69
Member

Simple optics also tells me that light doesn't go backwards (unless you put the reflector directly in front of the beam). What do I put in my pendants which also bounce light off the ceiling? The spherical LED light globes that I have seen don't exceed 100 lumens. My 20W CFLs provide over 1000.

I don't think switching to LED based lighting system is as simple as replacing your current lampss. If I wanted a LED lit household I would modify my electrical layout and select a set of luminaires s to take advantage of their lighting patterns.

Posted Saturday 24 Oct 2009 @ 12:32:54 pm from IP #
Greenozi
Member

I did some research yesterday on eBay and really LED lights are coming down in recent years to the point that makes retrofitting possible.
But I will wait for another reason.
Like all new inventions people try to use old stuff in new creative way. Get old heavy crap car replace engine and there it is – electric car.
Not something design with electricity in mind in first place.
Similarly LED lighting used in actual form (retrofitting old crap, halogen mountings loose the most future advantages they can offer.
Let’s see:
1. Home insulation.
Halogen mounting is design with excess heat in the mind. Perforated, to allow free airflow. Now our perfectly insulated homes with tones of bats on ceiling have holes that hot air flow at will. Advantage of LED low consumption that not pose overheating risk - lost. New frame should be mounted on ceiling surface not going through.
2Fashion.
All LEDs are packed into very compact unit resembling old-fashioned bulb. Luckily candles and kerosene lamp are out some time already otherwise manufactures needs to produce LED candles sitting on candle holder. Designers are free to create lighting design future any shape or size. Free your imagination!
3. Safety.
Due to close packed LED on small are the brightness is well above safe level for our eyes (retina) anytime direct glance at LED would cause temporary blindness. OK human eyes can handle this for some time but eventually (think your lifetime) give up and your vision drops. Spreading LEDs over bigger surface may alleviate this defect.
4. Future.
What I am really waiting for is flat glowing sheet 50 x 50cm that provide shade less lighting, resemble dispersed natural sun lighting, is efficient and omnipresent not like nowadays laser beam bright in one place and darkness in other, easy to clean due to uncomplicated shape. Future possible will be whole ceiling phosphorescently glowing but that next step after LED. At this moment the only available I found was growing LED light – 11 cm diameter lighting plate- quite awful design to be used at home yet.
5. New standard
Is needed for LED proprietary light source something originally design for LED and not replicable with incandescent lighting. Something like flat 5x5cm standardized lighting plates that designers can use now build modern lamps around. Not MR15 or G4 but new unique for LED, either 240V or 12V.

6...DC.
Last is quite futuristic but I can see less and less reason for AC at home and above. DC seems to be much more efficient for transitions line, modern devices at your home use DC comfortably. Switching to DC may also radically decrease harmful electromagnetic radiation omnipresent now. But that switch for global AC to DC need quantum leap in technical mentality.

Posted Saturday 24 Oct 2009 @ 11:45:27 pm from IP #
Sunshine
Member

Greenozi,

Re item 6:
That's the reason why we have AC power, as there is less transmission loss with AC.
DC power is uneconomic to transport any distance due to power loss.
To convert your house to DC power would mean a transformer on-site with extra cost of thousands of dollars, and with an efficiency loss of 5-6%.

Posted Monday 26 Oct 2009 @ 6:38:18 am from IP #
Greenozi
Member

Re 6 Sunshine. Actual facts actually may endorse my suggestion, so real question is even not if but when (transition from AC to DC will take place)
http://en.wikipedia.org/wiki/High-voltage_direct_current
....Advantages of HVDC over AC transmission....
and more
I don't want to write new chapter to wiki, but soon you will read another argument there. Superconductors. May carry only DC, and they are .. I guess .. 20 years away from industrial reality.

Posted Monday 26 Oct 2009 @ 7:10:23 am from IP #
rhills
Member

ericoppel said:
I have a 16 LED torch which I bought for $7 which is almost as bright as my old 35w 6v halogen spotlight and runs for hours longer on a standard lantern battery. It still amazes me every time I use it!

Any chance of sharing where you got the torch from?

Cheers,

Posted Monday 26 Oct 2009 @ 9:43:52 am from IP #
dymonite69
Member

Actually high voltage DC has less losses. The only problem is that my TV won't run on 10000 volts. AC allows you to step down. Inverting DC back to AC for this purpose entails power loss.

Posted Monday 26 Oct 2009 @ 10:45:28 am from IP #
Greenozi
Member

Don't forget that your solar PV is low voltage DC and is just right there that should be, at home to run LCD TV or Laptop. The beauty is they all mix perfectly, all this green energy resources,wind, solar, hydro, geo into one DC melting pot. I know already people running dedicated low voltage network at home for lighting. Anyway they are off the grid and doesn't make sense to covert 12V battery into 240V the to back 12V run LED lighting.

Posted Monday 26 Oct 2009 @ 11:47:40 am from IP #
dymonite69
Member

The fact is that lights aren't very power hungry. The problem is when you want to drive some big motors or compressors with your PV system.

Posted Monday 26 Oct 2009 @ 12:22:01 pm from IP #
Greenozi
Member

And that is just wonderful what you just said. "Lights are not power hungry". I remember time they were, that standard bulb was 100W or 200W. Few lights at evening home and it was kilowatt. Now whole lighting could be less then 100w. Same should happen to other home appliances TV maybe first, next air conditioning, cooking and cleaning. I would like to see similar revolution here that LED brought to lighting.
One more, long ago forgotten, is fluorescent paint. Accumulate photons during the day and lights all night.
Ceiling and walls painted this way beat even LED at efficiency - "0" energy consumption but I am not sure how to turn this lights off to sleep. Some money spent on research today may save a lot in future - maybe whole city just phosphorescently-luminescent?

Posted Monday 26 Oct 2009 @ 12:59:13 pm from IP #
Sunshine
Member

dymonite69,
I can't see any problem with big motors or compressors being run off solar PV.
Our large air con system and pool pump runs happily of the solar PV, even both at once, and we can still feed to the grid during the hours in the middle of the day.
If the solar PV can't supply enough, due to system size, time of day, and load, power is fed from the grid to make up the difference.

Posted Monday 26 Oct 2009 @ 1:18:21 pm from IP #
Greenozi
Member

One more sci-fi DC.
Lighting.
Energy of clouds could be one day captured one day through capacitors and then slowly released to the DC grid. Looks feasible with DC not so much with AC.

Posted Monday 26 Oct 2009 @ 1:28:32 pm from IP #
dymonite69
Member

Sunshine,

I would be interested to know the size of your PV system? If you are stand alone you would need quite a large one to run any three phase machinery.

Posted Tuesday 27 Oct 2009 @ 4:59:03 am from IP #
Sunshine
Member

It's a 3kW system. Output during the day for 4 hours peak is in range of 2400-2600watts.
I have a 6.2kW inverter aircon, which generally uses around 900w on a normal summers day. Pool pump is 1000w. So during the day, with both running will still see 500w exported.
I have two wireless power monitors so I can keep an eye on total inverter power output as well as total power export or import for the house in real time.

Posted Tuesday 27 Oct 2009 @ 6:33:45 am from IP #
ghostgum
Member

A better place for this posting would have been the recent discussion
http://www.ata.org.au/forums/topic/led-downlight-comparison-erroneous-claims
The Brightgreen website does appear to be one of those that provides adequate product information, except for the price. It gives power, lumens, and lux at varying distances.
Payback period in a residential environment looks more like 3-4 years.

Posted Friday 13 Aug 2010 @ 3:45:55 am from IP #
Diver
Member

Brightgreen were at the 2010 Melbourne designbuild expo. For added interest, video of exhibitor's interviews can be seen at the attached link:

http://www.homeimprovementpages.com.au/connect/designbuild_2010/

The post by Rebecca Cohen does however read like commercial spam. As such, it lessens the company's credibility.

Posted Friday 13 Aug 2010 @ 6:36:10 am from IP #
arthuritus
Member

This is probably too late for the original threaders (threadees?) but for others that stumble across this thread later, theres a website http://www.howmanylights.co.nz that shows you the output etc of a specific luminaire in a room. I'm not sure if theres an Oz version yet, could be worth playing around with different url endings. or google.

Posted Thursday 15 Dec 2011 @ 3:30:16 am from IP #
rockabye
Member

A field trial of LED light fittings in social housing says the new technology can deliver huge energy savings, reduce costs and makes residents feel safer.

http://www.bbc.co.uk/news/science-environment-16199552

http://www.energysavingtrust.org.uk/Publications2/Energy-efficiency/Lit-Up-an-LED-lighting-field-trial

Posted Sunday 18 Dec 2011 @ 7:13:09 pm from IP #

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