Bathroom downlighters

[diyhell]

Am swithering over whether to put in 12v halogen downlighters into my bathroom or those new fangled LED ones.

Having put the standard 12v halogens into a previous bathroom I know that I need 6 x 20w. Haven't a clue with the LED ones though (and anyone know a good article on calculating lux?)

Anyone had any experience of them? They seem like a good idea with long life and low running cost.

 

[breezer]

where are you getting the lights from? ask them.

I looked on the tlc website, they do not sell led lights other than for walkover etc (v good for a bathroom though) how ever they do supply "led gu10 lamps" so, so long as the fitting is suitable for a bathroom, you could get mains gu10 lights and put mains gu10 led lights in instead. tlc say the light output is 20watts

i personally do not like the "white ones" as in my opinion they have a slight blue tint

 

[dingbat]

tlc say the light output is 20watts

That's the power consumption - or are they saying it's equivalent to, say, a 20W halogen? When we only had incandescent lighting wattage gave a reasonable comparison of light output, but florries and LED's are much more efficient. (They have a higher 'luminous efficacy')

It could be many years before the general public come to intuitively understand Lumens/Lux the way they can currently imagine the difference between a 60W and a 100W lamp and I freely admit I have no idea how bright a '20W' LED lamp actually is.

 

[plugwash]

yeah i think LEDs are like CFLs sold by what incandescent bulb they are closest to

btw one important thing to remember about most varietys of non incandescent lighting is that they have a low colour rendering index which can make some things look the wrong colour

 

[dingbat]

yeah i think LEDs are like CFLs sold by what incandescent bulb they are closest to

Hmm, not sure about that one - is a 7W CFL the same as a 40W tungsten, or a 60W? All the CFL's I've ever used are rated by power consumption - pushing the low running cost rather than the light output. I have no idea what's equivalent to watt(sic) any more.
I do agree about the colour rendering though and one other thing - spread of light; the peddlars of downlights have a lot to answer for in homes now using four times as much electricity as before to get some pretty uneven lighting.

Has anybody seen a good, no-nonsense guide for comparing different types of light. (I'm thinking of Ban, here - if he's not found one then one surely doesn't exist )

 

[diyhell]

Has anybody seen a good, no-nonsense guide for comparing different types of light. (I'm thinking of Ban, here - if he's not found one then one surely doesn't exist )

Exactly what I could do with Dingbat. Anyone know of one?

 

[breezer]

different colours of light from a lamp is refered to as colour temperature, its measured in degrees kelvin, dont know what kelvin has to do with it but it is

 

[plugwash]

color tempreature is not color rendering index

color rendering index is a percentage

a pure incandescent light will have a color rendering index of 100%

so will any other body that gives out light BECAUSE it is hot

remember the eye has 3 color receptors

each one senses not a single wavelength but a range of wavelengths with different sensitivities

it therefore follows that there are multiple combinations of wavelengths that can make them same apparent color to the eye

a lights color tempreature is the tempreature of object that has the same apparent color as the light however a non heat based light may be making this apparent color with a very different wavelength combination to the hot object.

so just because a light has a particular color tempreature does not mean that stuff would look the same under that light as under the light of a hot object of that tempreature

 

[ban-all-sheds]

Has anybody seen a good, no-nonsense guide for comparing different types of light. (I'm thinking of Ban, here - if he's not found one then one surely doesn't exist )

The Force is weak in this one...

Sadly, I've not found such a guide, but I wish there was such a thing, and data to help plan how many downlighters a given area needs etc.

I'd probably start with major lighting manufacturers - GE, Philips etc - see if they could help?

 

[securespark]

I've heard that Osram (my favourite lamp mfr!!!!) do a reasonable effort.

 

[Damocles]

Since LEDs by their nature only emit light of one pure colour, just exactly what light comes out of a so-called white one? Does it really contain several coloured leds together?

 

[breezer]

(scotts accent) "its the laws of physics jim"

white light, is actually a mixture of all the primary colours of light at the same intensity, they can not make a pure white led, as i said it has a blue tint.

 

[plugwash]

Since LEDs by their nature only emit light of one pure colour, just exactly what light comes out of a so-called white one? Does it really contain several coloured leds together?

i think they are a blue LED internally with some form of flouresent material on them to try and fill in the other colors

 

[securespark]

STOP PRESS!!

I have found a lamp guide of sorts.

DENMANS have printed a Lamp Guide 2005 which has a table listing:

Lamp types, Efficiency (lumens/watt), colour rendering and colour temp.

See your branch of Denmans for details.

 

[dingbat]

Yeah, I picked one up the day after mentioning it... but I've been too busy to actually read it!