advertisement


LED light bulbs - some questions before buying

avole

The wise never post on Internet forums
Hi all, and yes, the "Green" thread got me thinking. Are LED light bulbs (I assume they do exist, never asked nor seen at my local Bi1) good for both you and the environment ?

Are there other alternatives that use less energy?
 
OK, it's good, heading off now. They happen to be on special at a couple of euros each at my local.

Can someone lock or delete this thread?

Cheers :)
 
Like all things - LED bulbs continue to get 'better' and 'more varied' as new models come along. Newer models can replace even some of the bigger old fashioned bulbs now - so those people who hoarded old-fashioned 100W bulbs (I know one) can start to relax. Even car headlamps are becoming quite common as LEDs.

The energy saving across Europe as billions of bulbs are switched over is significant. All of our office Fluorescent fittings have been changed - the new lights are so much nicer and no flicker!
 
Until they routinely have a colour rendering index (CRI) above 90 they will cast an unpleasant light. Most have a CRI of around 85. Incandescent bulbs were around 96.
This I learnt from an earlier thread in this forum, when I posted about having put warm white led bulbs in my kitchen while my wife and daughter were out, and their walking in and expressing immediate dismay at the lighting.
 
I changed every bulb in my house inc bed side lamps , cooker hood all to LED's , Mainly as a cost saving project , No regrets so far and all the original bulbs are still in place , No failures
 
The other thing that's not obvious before you fit them is that your old tech dimmer switches don't work very well at the low settings and the lights may flicker. Presumably you will need low wattage dimmers...more expense that you need to factor into your 'savings'.
 
All of our office Fluorescent fittings have been changed - the new lights are so much nicer and no flicker!

I time my TT using an LED lamp.........

Incandescent bulbs were around 96.

No they don't, they have a CRI of 100 - incandescent are continuous spectrum so cannot, not have a CRI of 100. I've not looked online, but as the LED lamps here are continuous spectrum (as viewed using a spectroscope) they will also have a CRI of 100.
I can only assume that you are confusing CRI and CCT (colour-rendering index (also known as Ra) and colour corrected temperature).
 
Hi all, and yes, the "Green" thread got me thinking. Are LED light bulbs (I assume they do exist, never asked nor seen at my local Bi1) good for both you and the environment ?

I have no idea about the production techniques, though sadly one can assume they are made with cheap labour in environmentally toxic parts of China. As is everything else cheap we consume, even much modern “British” hi-fi! That said they are wonderful things IMO, very low energy, long life and they don’t have that awful green colour cast of fluorescent energy bulbs. I also get the impression from what little I’ve been able to dig up that they have less UV output than either incandescent or fluorescent bulbs, so may prove much kinder to fragile vintage plastics (e.g. old computer cases that so often ‘yellow’). Time will tell on that one, but I’m hopeful they are a safer light source.

I also love the modern WiFi control available, a fair bit of my house runs on a Hive system so I can set timers for some lights, control and dim others from my iPad etc. The fact I can turn my 70 year old Anglepoise 1227 on, off or dim it via my iPhone from anywhere in the world is rather amusing!
 
This site contains affiliate links for which pink fish media may be compensated.
I also love the modern WiFi control available, a fair bit of my house runs on a Hive system so I can set timers for some lights, control and dim others from my iPad etc. The fact I can turn my 70 year old Anglepoise 1227 on, off or dim it via my iPhone from anywhere in the world is rather amusing!
Thereby offsetting the energy savings of LEDs by increased energy use with data used for the "internet of things"?
 
This site contains affiliate links for which pink fish media may be compensated.
Be careful, cheap ones are unreliable, dimmable ones don’t dim properly and the light many cast is horrible. On top of that if you use DAB many can interfere with it and even knock it out completely. You pays your money...,
 
Until they routinely have a colour rendering index (CRI) above 90 they will cast an unpleasant light.

We have replaced all our lights with LEDs and not one casts an unpleasant light. We did put some "cold" LED 5ft strip lights on our kitchen ceiling to replace the old fluorescent tubes and the lighting is way better.
 
Thereby offsetting the energy savings of LEDs by increased energy use with data used for the "internet of things"?

Offsetting some, I haven’t done the math, but I bet leaving them all on all day is still way more efficient than an hour of a fluorescent bulb! They really don’t use much energy at all.
 
, but as the LED lamps here are continuous spectrum (as viewed using a spectroscope) they will also have a CRI of 100.
What LED lamps have you found with a CRI of 100? Online they all quote 86 or thereabouts, except some Philips GU10s. I need GU5.3 and small screw.
 
No they don't, they have a CRI of 100 - incandescent are continuous spectrum so cannot, not have a CRI of 100. I've not looked online, but as the LED lamps here are continuous spectrum (as viewed using a spectroscope) they will also have a CRI of 100.
You're right. My mistake. It's halogen which are 95. That's why they are, to me, an acceptable alternative to incandescent while most LED aren't.
There's a good website, well-lit.co.uk, that gives examples of how colours look different depending on the CRI.
 
No they don't, they have a CRI of 100 - incandescent are continuous spectrum so cannot, not have a CRI of 100. I've not looked online, but as the LED lamps here are continuous spectrum (as viewed using a spectroscope) they will also have a CRI of 100.

I’m trying and failing to find any indication as to whether LEDs are likely to be kinder to old plastics. The suggestion is ‘probably’, but getting to any rational is hard. It is strongly suspected in the vintage computer collector scene that fluorescent lighting plus heat was the absolute worst and is likely responsible for the old computers that have gone a really ugly yellow-brown, but I’ve not been able to dig up much real scientific evidence here as to exactly why and what was so awful about them. I’ve got a couple of cool old computers and phones boxed up I’d dig out and stick on display if I was fairly confident they wouldn’t yellow with modern LEDs.
 
CRI is a function, very largely, of how near to full spectrum any light source is, not that even very high CRI fluorescents, used specifically for colour matching in print works and the like, are anything like full spectrum.
Perhaps I could get some missing lines in the LED spectrums here by closing the slit on my spectroscope right down, but the lamps here are SO close to full spectrum that they appear to be full. Looking online, quickly, I can't find a CRI quoted for lamps on LED Hut website. Also take a look at Wikipedia to see how the two types of "white" LED work, and their spectra. A CRI down in the mid 80's seems remarkably unlikely for phosphor based LED lamps.

Degredation of plastics is MOSTLY down to UV and although standard glazing is a VERY good UV absorber, it isn't 100%. UV causes colours to fade and plastics to become brittle. Plasticised plastics will forever leach plasticiser as plasticisers are mostly (but not exclusively) oily liquids, so they simply diffuse out. Diffusion rate increases with increasing temperature.
It WILL be online somewhere - try to find an archivists' forum and ask there even, but I am not sure what the brown discolouration is, as it has been unimportant in the areas with the plastics industies that i have worked in, but I would tend to bet on some kind of diffusion/surface degredation combining with general atmospheric muck, or even reacting with packaging materials, or mobile components within the pacakging materials (cardborad generally smells reasonably strongly, so will be full of volatile/mobile gubbins). Perhaps the best way to keep things like computers would be inside a thick, sealed, old-fashioned polyethylene bag?
 
It's halogen which are 95

Halogen are 100 too - continuous spectrum again - the heat and light is generated from molecular vibration, which is random, not electronic tramsformations, which are quantised and hence of specific "colour", but running hotter than standard incandescent, they emit more light towards the blue and less towards the red - that is a higher CCT but conventionally gets called "cooler".
 


advertisement


Back
Top