Using Rough Service light bulbs in the home

[aptsys]

Incandescent lamps have a much nicer "soft glow" when run at half voltage, that effect cannot be achieved with LED lights

Philips Warm Glow do an excellent job of recreating the effect.

 

[bernardgreen]

Philips Warm Glow do an excellent job of recreating the effect.

The spectrum from the LEDs is not the same as the much broader spectrum from a filament glowing red hot

I like the simplicity of connecting two 230 lamps in series to obtain soft lighting

 

[JohnW2]

The spectrum from the LEDs is not the same as the much broader spectrum from a filament glowing red hot

I'm not saying that anyone has precisely achieved it, but I presume that there is no theoretical reason why an appropriate combination of LED elements and/or phosphors cannot produce any frequency spectrum one wants. Some currently available ones seem to get pretty close to true ('broad spectrum) 'daylight' ...

Kind Regards, John

 

[fluorescence]

I'm not saying that anyone has precisely achieved it, but I presume that there is no theoretical reason why an appropriate combination of LED elements and/or phosphors cannot produce any frequency spectrum one wants. Some currently available ones seem to get pretty close to true ('broad spectrum) 'daylight' ...

.......

Kind Regards, John

Correct but usually these type of lamps have a few drawbacks; high cost, lower lumens per watt than most LED lamps* and 5000k is not what most people in the UK consider 'soft' lighting. Not sure if these high CRI lamps come in warmer colours?

*yes I know the lumens per watt for incandescent lamps is appalling

 

[bernardgreen]

no theoretical reason why an appropriate combination of LED elements and/or phosphors cannot produce any frequency spectrum one wants

the warmth of an under run incandescent lamp includes infra-red radiation, does the body / eye sense and react to this invisible radiation ? I think it does.

Can a phospher convert UV from an LED element into infra-red ? I don't know of any... and if there was using it would been seen as creating heat and thus wasteful.

 

[JohnW2]

Correct but usually these type of lamps have a few drawbacks; high cost, lower lumens per watt than most LED lamps* and 5000k is not what most people in the UK consider 'soft' lighting. Not sure if these high CRI lamps come in warmer colours?

It was really the concept (that LEDs can be manufactured with virtually any spectrum one wants) that I was mentioning and illustrating, rather than the specific product.

Kind Regards, John

 

[JohnW2]

the warmth of an under run incandescent lamp includes infra-red radiation....

It does - and the fact that much/most of the radiation from an incandescent bulb/lamp is not visible is (as you go on to sort-of acknowledge) the main reason why they are so inefficient in converting electricity into visible light.

... does the body / eye sense and react to this invisible radiation ? I think it does.

The body obviously does sense IR, indirectly, as the consequential temperature rise of the skin. As for the human eye, the answer is essentially 'no' - to quote from one of the many papers out there ...

At 1050 mμ the sensitivity of the peripheral retina is only 3×10−13 times its maximum value at 505 mμ. A computation shows that by 1150 or 1200 mμ radiation should be more readily felt as heat by the skin than seen as light by the eye.

Can a phospher convert UV from an LED element into infra-red ? I don't know of any

I don't know whether it is done with phosphor(s) or by intrinsic behaviour of the device but, as you know, one can get 'IR LEDs', so it presumably must be theoretically possible include IR in the spectrum of a manufactured 'LED'.

... and if there was using it would been seen as creating heat and thus wasteful.

Exactly - and, as above, not without reason.

Kind Regards, John

 

[bernardgreen]

one can get 'IR LEDs'

but IR would not active the phosphers need to produce the visible part of the spectrum.

"""the sensitivity of the peripheral retina is only 3×10−13 times its maximum value """

I do not doubt that, but there is still "sensitivity" and the human brain and its associated sensors can react to extremely small small inputs. And are there figures for the retina other than peripheral ?

Personally I think that the desire to save energy has gone too far in some areas. The temperature of a room that is lit with warm light can be set a few degree lower than a room that is lit with "energy efficient" ( cold ) lighting and still feel as comfortable. ( source :- research by the architectural department of a university a few years ago )

 

[JohnW2]

but IR would not active the phosphers need to produce the visible part of the spectrum.

Possibly not (although I don't know) but, as I implied, given methods whereby LEDs can be made to produce radiation in the visible, IR and UV parts of the spectrum, I am sure it would not be beyond the wit of many to manufacture a product which emitted light in whatever parts of thoise spectrum one wanted.

I think it's easy to forget that, in terms of the physics, there is nothing special about 'visible light' - it's just a tiny part of a very wide spectrum which happens to be that part of the spectrum to which most biological eyes developed sensitivity when they evolved millions of years ago.

"""the sensitivity of the peripheral retina is only 3×10−13 times its maximum value """ ....
I do not doubt that, but there is still "sensitivity" and the human brain and its associated sensors can react to extremely small small inputs. And are there figures for the retina other than peripheral ?

I should have mentioned that I quoted the bit about IR sensitivity of the peripheral retina (primarily 'rod' receptors) because it is 'much more' IR-sensitive than the central retina ('fovea', primarily 'cone receptors') - i.e. central retinal sensitivity to IR is extremely low.

Whilst what you say about the ability of the brain to react to extremely small inputs is true, 3 x 10^13 is an extremely large ratio ... imagine something that was emitting visible light and which appeared quite bright when viewed at a distance of 1 metre. How 'bright' do you think your eye/brain would perceive it if it were moved to a position about 5.5 million metres (5,500 km) away (√(3 x 10^13) being about 5.5 million)?!

Personally I think that the desire to save energy has gone too far in some areas.

I totally agree, but I think that incandescent lighting is so inefficient (particularly when heating is not required) as to deserve being 'singled out' for particular attention.

The temperature of a room that is lit with warm light can be set a few degree lower than a room that is lit with "energy efficient" ( cold ) lighting and still feel as comfortable. ( source :- research by the architectural department of a university a few years ago )

I don't doubt that (and similar can be achieved by changing furnishings/decor) - but, as I've been saying, I also doubt that it is beyond the wit of man to produce light which is 'warm' (in the perceptual/psychological sense) in a manner far more efficient than incandescent bulbs/lamps could possibly manage - hence the best of both worlds.

Kind Regards, John

 

[winston1]

The temperature of a room that is lit with warm light can be set a few degree lower than a room that is lit with "energy efficient" ( cold ) lighting and still feel as comfortable. ( source :- research by the architectural department of a university a few years ago )

Interesting. I wonder if that is why in tropical climates cool white tubes are mostly used whereas in temperate climates warm white tend to be used

 

[ericmark]

The problem is there is no single factor.
1) I am getting older so likely now need more light.
2) The eye is more receptive to some colours, I was told we see better with Orange light that is why Son lamps worked so well, however that may be a myth.
3) The higher the colour temperature to brighter we tend to think it is, even when lumen wise it is not.
4) Flashing a light fast we tend to see more than same average watts without flashing, but lumen is the same.
5) The base of CFL and LED means the angle of spread has changed.
6) The ceilings don't collect dust as much as less air circulated around the lamps due to lower heat.
So 1979 when I moved into house main room 2 x 100W tungsten, changed to 6 x 40W to 60W tungsten depended what was in stock, then 11W CFL, fittings changed to SES then 10 x 5W CFL (too dim really), swapped to 10 x 3W LED, seemed brighter but found needed a standard lamp to read so not 10 x 5W LED so ¼ the original watts. Main difference is not swapping a bulb every other week.

Since using gas heating they do save money, however as to saving energy not so sure, I have found the idea of changing the temperature of a room through the day simply does not work. It takes too long to heat and cool a room, over night so 8 hours heating totally off heart of winter room temp drops 21°C to 17°C i.e. 0.5°C per hour when outside temperature below freezing. Heating up the room also slow because of the anti-hysteresis software, so 17°C start set to 20°C and looking at around 3 hours, set to 24°C and up to 20°C within the hour, but then likely to over shoot, so raising temperature 1°C per hour.

So temperature wanted 8 am to 10 am 20°C as time I get up and shower so undressed, 10 am to 6 pm 18°C as working so don't need it too warm, 6 pm to 11 pm 22°C as sitting doing nothing just watching TV and 11 pm to 8 am 16°C as in bed.

You simply can't heat and cool quick enough to get those temperatures, however the inferred from the tungsten bulb was near instant, so as an integrated system it worked well, however I don't want to be changing bulbs every two weeks, so sticking with LED.

It seems bulbs can last

reading this report it seems bulbs can last over a 100 years, however not tungsten it was carbon-filament. And now giving out around 4W of light but was designed to give out 60W of light. OK this is getting silly as 4W of light is rather low, however bulbs have run for many years, but as to how often switched off not easy to say.

I know I have found strings of rough service lights that have been installed for years down tunnels. but my garage is only place left using BA22d bulbs, and I must have around 50 bulbs left, lights switched on average of 1 hour a week, will not run out in my life time.

 

[JohnW2]

... so ¼ the original watts. .... Since using gas heating they do save money, however as to saving energy not so sure...

Well, one certainty is that they are bound to save energy, as well as money, at times of year/day when heating is not required.

Kind Regards, John

 

[JohnW2]

Interesting. I wonder if that is why in tropical climates cool white tubes are mostly used whereas in temperate climates warm white tend to be used

Possibly. As I hinted, even when lighting is not needed, people tend to 'feel warmer' (for a given actual temperature) when decor etc. is at the red end of the visible spectrum as compared with decor etc. at the blue/violet end of the spectrum.

Kind Regards, John