LED's are typically 40 to 50% efficient. Incandescent, depending on the type of lamp and their intended life, are typically 10 to 20% efficient. The inefficiency proportion of both types, being dissipated as unwanted heat.
Are LEDs a big con?
- Thread starter d000hg
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LED's are typically 40 to 50% efficient. Incandescent, depending on the type of lamp and their intended life, are typically 10 to 20% efficient. The inefficiency proportion of both types, being dissipated as unwanted heat.
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Well it's funny you say that, when I was in Wickes they had some little LED torches for £1, my 9 YO grandson was with me and promptly picked one up to play. There were 6 different colours so I purchased one of each and it has now become second nature to pick one up when popping out in the dark. Our 80YO neighbour does the same and a running club all wear lights now which wasn't needed before changeover.You do realise that the purpose of street lighting is NOT to light up people (and other things) ?
The idea is that you provide a lit background, against which objects will appear in silhouette if not directly lit. And the disjointed pools of light still provide that. I do agree though that it's not as nice to walk in when there are pools of light with dark in between.
Oh how things have changed, remember the days when you always thought about how long you'd be out - and make sure you had a torchif it was likely to be darkSome of my friends still do
Some of our road is so dark it's not possible to see the edge of the kerb in places.
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I am not so sure the waste from any light source is heat, if you consider only visible light part of the electromagnetic spectrum is required, then any UV or infrared is waste as well as heat, most the energy should be retained in the home if blackout curtains are closed, other wise energy will escape from windows, however we see instructions as to length of cable between an electronic transformer and a quartz lamp, because at kHz frequency it can transmit radio waves, replacing a quartz lamp with a diode one can very likely produce a transmitter. I note many G5.3 MR16 lamps have 50 Hz marked on the lamp
this is from Screwfix advert in the description there is nothing to say AC or 50 Hz just an advisory note "Please check the suitability of your transformer before selecting your LED MR16 light bulb." which does I suppose say it should be a transformer not a power supply.
I suspect a zero to 60 VA electronic transformer would power the light just the same as a toroidal transformer, and likely it would also work with DC. However what we don't know is does it have a full wave rectifier inside or half wave, and if the rectifiers diodes will take double the current when supplied with DC or will it become a radio transmitter if supplied with kHz AC. This is why I prefer GU10 there is no question if the supply is suitable for the bulb.
But we see lumen output quoted and in my old house I used good quality Philips bulbs golf ball CFL 8 watt each x 10 so lumen output for room 4250 lumen and the room was dark, I replaced these with 3 wall candle LED lumen output 2800 lumen brighter but not bright enough so went to 5 watt and then bit too bright at 4600 lumen, so it is clear there is some thing wrong with lumen as to light output, it is claimed lumen is a measure of the light we see by, so does not include UV or infrared but experience has shown me different, also experience has shown me cheap bulbs last longer than expensive ones, the dinning room had same lights as living room, within a year bulbs were failing, so my wife got 6 cheap CFL from HomeBargains again 8W and same lumen output, but much brighter, maybe there is a special Philips lumens?
The move to LED was to start with an accident, I bought 2 LED candle bulbs 1.8W from Lidi to try then in reading lamps, on getting home I found another 2 CFL had failed so put in the two LED bulbs as a temp until we could get some more 8W. I was surprised on how good they were. Lidi sold out and next time they did E14 candle bulbs they were 3W.
Odd but some 6 years latter the HomeBargains 8W globe bulbs CFL are still working in my dinning room, not one has failed.
I suspect a zero to 60 VA electronic transformer would power the light just the same as a toroidal transformer, and likely it would also work with DC. However what we don't know is does it have a full wave rectifier inside or half wave, and if the rectifiers diodes will take double the current when supplied with DC or will it become a radio transmitter if supplied with kHz AC. This is why I prefer GU10 there is no question if the supply is suitable for the bulb.
But we see lumen output quoted and in my old house I used good quality Philips bulbs golf ball CFL 8 watt each x 10 so lumen output for room 4250 lumen and the room was dark, I replaced these with 3 wall candle LED lumen output 2800 lumen brighter but not bright enough so went to 5 watt and then bit too bright at 4600 lumen, so it is clear there is some thing wrong with lumen as to light output, it is claimed lumen is a measure of the light we see by, so does not include UV or infrared but experience has shown me different, also experience has shown me cheap bulbs last longer than expensive ones, the dinning room had same lights as living room, within a year bulbs were failing, so my wife got 6 cheap CFL from HomeBargains again 8W and same lumen output, but much brighter, maybe there is a special Philips lumens?
The move to LED was to start with an accident, I bought 2 LED candle bulbs 1.8W from Lidi to try then in reading lamps, on getting home I found another 2 CFL had failed so put in the two LED bulbs as a temp until we could get some more 8W. I was surprised on how good they were. Lidi sold out and next time they did E14 candle bulbs they were 3W.
Odd but some 6 years latter the HomeBargains 8W globe bulbs CFL are still working in my dinning room, not one has failed.
In many cases the LED element only produces UV "light" which activates a phosphor to produce light of the required colour
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The difference though, is that most of the waste energy from an incandescent lamp is radiant heat which is radiated along with the light out of the front of the fitting.
I admit I don't understand your point there. Waste heat from an incandescent lamp is radiated in all directions. I appreciate it will not always be wasted, especially in winter, but it only has value when a room is electrically heated and the tiny amount of extra warmth created has little value.
In summer, the waste heat from incandescent lighting can in some circumstances, be a bit of a problem.
The heat from the incandescent bulb comes from the filament and bathes the room in heat as well as light
The point made is with LEDs the heat is generated further back inside the housing behind the LEDs so is going to be distributed into the ceiling or whatever.
A reasonable point though I've no idea how hot they actually get.
That isn't true.
Chinese factories can turn out BMW car parts or Osram light bulbs built to specification and with quality control.
Or, if you want to buy cheap, they can turn out cheap.
You can have whichever you want.
Your choice.
My test would be, is it bright enough to be able to spot dog **** before I step in it?
That is wrong! Just like we did, China turns out some unreliable rubbish and the high spec. reliable stuff too. Many of the top name things you buy in the UK, like the rest of the world, is made in China or contains many parts made there.
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Some good points, if you are wearing an orange jacket you will stand out better in orange light, if the jacket is yellow you will stand out better in yellow light not sure why railway workers wear orange and road workers wear yellow, must be a good reason some where, I find in the main turn a CD to refract the light from LED and it is reasonably even across the spectrum, but fluorescent is in bands.
It is one of the tests for colour photography, with mono chrome we would use red filters I think it was a long time ago when I did mono chrome, to bring out the clouds. Today the camera has built in filters so even in mono chrome mode it still takes in colour, so may as well set it to RAW and adjust later with software.
But the camera does not seem to work like our eye, I have taken pictures where too dark to see and failed to take them when I could see quite well, so in a room with CFL I have used 1/30 second at f2.8 with 100 ISO but with LED which seemed brighter it was 1/20 second at f2.8 with 100 ISO so the camera actually considered the LED not as bright as the lumen indicated, but the eye seems better suited to LED, likely due to the colours and what colour the cameras sensor was more sensitive to.
It is one of the tests for colour photography, with mono chrome we would use red filters I think it was a long time ago when I did mono chrome, to bring out the clouds. Today the camera has built in filters so even in mono chrome mode it still takes in colour, so may as well set it to RAW and adjust later with software.
But the camera does not seem to work like our eye, I have taken pictures where too dark to see and failed to take them when I could see quite well, so in a room with CFL I have used 1/30 second at f2.8 with 100 ISO but with LED which seemed brighter it was 1/20 second at f2.8 with 100 ISO so the camera actually considered the LED not as bright as the lumen indicated, but the eye seems better suited to LED, likely due to the colours and what colour the cameras sensor was more sensitive to.
With pretty much all LED lamps quality is key if you want decent light output, no noise, and that lasts. Things to consider if changing straight over low voltage using the existing transformer 12v they are not made to run led lamps but they may run them badly causing flashing and shortened life. GU10 should be fine but get goods ones. I would recommend Enlight who are actually Aurora lighting they give decent life and lamp performance also offer the colour of choice in terms ok Kelvin rating Higher the number brighter or whiter the look. Always check the lumen output, cheap ones generally give absolute crap output.
The yellow jackets might be down to long term use of sodium lighting - sort of goldish colour but probable really down to car headlights and fluorescent jackets which can also stand out in daylight.
Typical white light leds actually emit 3 distinct colours. They are a lot more light efficient than filament bulbs but har read that some may not be as efficient as sodium lighting. Fluorescent lighting can emit far more different colours so currently specialised tubes are still best for colour critical work.
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