LED desk lamps

[Psi*]

I don't really consider myself green as in I rarely go out of my way to be green or reducing my carbon footprint ... per se. I am all about saving a nickel tho and if green occurs, then I will comment about it but not proselytize the instance as being green.

In this case I am interested in cutting down the electric bill a bit, but most interested in cooling my office down. I have been watching the whole anti-incandescent bulb to CFL thing for sometime. I have a few CFLs for those rare lights that qualify ... the ones that are on for long periods of time. More recently in the final remodel of the kitchen (wife is a high end chef & caterer so this is not your mother's kitchen unless she too had a similar occupation) I had installed LED under cabinet lights. We went thru 2 different versions ... again the chef had distinctly crisp opinions ... in a manner of speaking. But I digress.

With that kitchen as inspiration, I decided to replace my touch controlled halogen desk lamps. I really liked these lamps as they have 3 different intensities available at a mere touch ... so typical me.Yet I am quite aware of the warning on the diffusers to ensure that they are in place to reduce UV exposure. Hmmm really? So after about 5 years of use and careful bulb replacements ... and these are the kind that you do not touch with your fingers less the skin oil creates a hot spot & early burn out ... I found some acceptable LED replacement lamps. Of course they are touch controlled also.

This is the one, Energy Efficient Flexible Neck LED Desk Lamp, touch controlled tho only on/off. That is fine as I used the lower intensity on the halogen lights to reduce heat. The heat in the hologens was at over 270 F (I have a pyrometer ... would you expect anything less???) If the hogens had been on high for some period of time, everything in the area was warm to hot & these lamps were about 18" over the desk.

These little LED disks can be position a little more than a foot over the base. This gives acceptable light dispersion. I do kind of wish there was a little a diffuser as even an optional attachment, but not a big deal actually. So for 3.5 watts & nearly identical light intensity (LEDs are more white), the $68 cost does mediate how many one might buy, I would recommend these over anything else I can find on the market. I did buy 4, 2 for my wife & 2 for my desk.

My office is much more comfortable for myself & the computers.

 

[Tharic-Nar]

I have experimented with LEDs in the kitchen. I have Halogen down-lights dispersed throughout the ceiling and they inevitably blow at some point. So, I went and looked around for LED replacements to save the cost of constant replacement and to save a bit of power as a result too.

Picked up 2 different colours, Amber and White, to try them out. Yee gods, the colour was awful. The White was blue (as is typical of LEDs) and the amber was not the comfy 5.4k but more of a brilliant yellow. What a waste of cash that was.

There isn't a replacement to Halogen lamps in terms of light quality. LEDs are fine if you get used to colour, but I always find them too blue and very poor for contrast. They also make it difficult on the eyes when switching from light to dark rooms. LEDs still produce heat too, but nowhere near as much as Halogen. I'm more inclined to go CFL than halogen myself, but then the whole Mercury, UV leakage, exploding transformers etc kind of put me off a bit, despite using them around the house.

As for going green... I do recycle, quite a lot, but when it comes to power, I'm just in it to save money if I'm honest... Says he with a 500+ Watt PC...

 

[Psi*]

Yup, the these LED lamps are a definite shift from the yellow part of the spectrum that incandescents & halogens are in. I forgot that I did immediately notice ... and immediately forgot ... again.

When making the changes it is more complicated than just noting actual power, equivalent wattage, or lumen output. And, what you choose may depend on where you use it.

But, my office is soo much cooler now

 

[Rob Williams]

Are all white LEDs off-white? Is there such thing as a white LED that's pure white, even if it's expensive? I'm not sure what kind of bulbs I am using at the moment, but they are energy-efficient (spiraled), and are equivalent to 100W bulbs but draw something like 23W. I've considered LED before but not even sure if those are common as room lights to replace typical light bulbs.

 

[Psi*]

Sounds like you have compact fluorescent... aka CFLs. Since your already running these I am not sure that I would bother with a change out to LEDs.

Pure white as in sun light? Or, just whiter than incandescents or halogen? In that case these are just below day light at high noon (literally) and more white that the halogens. I cannot call them blue as Tharic-Nar has experienced. But as he indicated warmer lighting does aid in reading and contrast ... there are loads of auto-enthusiast forums with information on that topic. But, reading from what? Text on the printed page (which ought to off-white for optimal contrast ... they say). Or, text on an LCD display? In my judgement, the LED desk lamps + LCD display is the slightly better combination.

Mind you, I had 2 halogens in my office as I found a distributed lighting in the office to be very comfortable for working for hours at a time. The point is, those 2 halogens, even dimmed, put a hellacious amount of heat into the office despite ceiling fans & cross ventilation. The 5 computers had their own contribution of course. But the heat radiation off the halogens is pretty remarkable.

With these LEDs, which do not have a dimming setting, I keep thinking that they are hot but I can touch them without issue. The halogens measured ~270 deg F with my infrared thermometer (aka pyrometer); the LEDs measure ~97 deg F and the room temp is 80.

 

[Rob Williams]

Pure white as in sun light? Or, just whiter than incandescents or halogen? In that case these are just below day light at high noon (literally) and more white that the halogens. I cannot call them blue as Tharic-Nar has experienced. But as he indicated warmer lighting does aid in reading and contrast ... there are loads of auto-enthusiast forums with information on that topic. But, reading from what? Text on the printed page (which ought to off-white for optimal contrast ... they say). Or, text on an LCD display? In my judgement, the LED desk lamps + LCD display is the slightly better combination.

Is sunlight even considered to be pure white? I guess I just like bright white because it's the purest color, and doesn't add a "tinge" to things around the room. For example, I am looking at a white motherboard box at the moment and it looks kind of beige. Of course, I guess the fact that the light is bouncing off of beige walls doesn't help.

For photography reasons, I'd like to get bulbs that are as pure white as can be, since I don't have enough space to want to move a photography tent around all the time. Though, thanks to the blessing that is Photoshop, issues like color tinges can be easily worked around.

With these LEDs, which do not have a dimming setting, I keep thinking that they are hot but I can touch them without issue. The halogens measured ~270 deg F with my infrared thermometer (aka pyrometer); the LEDs measure ~97 deg F and the room temp is 80.

That's what intrigues me. Summer is right around the corner, and using a temp gun, I can see the bulbs I am using now, despite being energy efficient, still emit heat of over 50ºC in some parts. That's too hot... way too hot. But at the same time, I do appreciate 100W equivalent brightness...

 

[Kougar]

The only thing I can say about LEDs is that to remember they are a directional light emitter. Unlike fluorescents and incandescents which emit light in all directions, LEDs emit a focused light in a single direction. I can't find the ratio, but over half of the light from a LED source goes only where it is pointed, basically like a spotlight. Except each LED bulb is a self-contained spotlight. So for lighting up a general area like a full room or the entire desk, this needs to be kept in mind. They can create harsh, unevenly lit areas.

I know some fancy (and expensive) LED "bulbs" point LEDs in multiple angles and/or use diffusers to mitigate this effect, but that doesn't solve the issue and both options only cut down on the amount of light.

LEDs still produce heat too, but nowhere near as much as Halogen. I'm more inclined to go CFL than halogen myself, but then the whole Mercury, UV leakage, exploding transformers etc kind of put me off a bit, despite using them around the house.

That's the kicker. It seems like all the cheap CFLs base lifespan ratings on extremely low temperature environments. Stick a 20w CFL in a socket that held a 100w bulb, and the thing can actually get warm enough to dramatically shorten its own lifespan. I've seen the things discolor and yellow the plastic from its own heat even inside a lamp built to hold a 100w incandescent bulb, go figure.

Are all white LEDs off-white? Is there such thing as a white LED that's pure white, even if it's expensive?.

Is sunlight even considered to be pure white? I guess I just like bright white because it's the purest color, and doesn't add a "tinge" to things around the room.

Sunlight is not pure white, it's a "warm" color with plenty of yellow... incandescents and (by now) most CFLs are tuned to emit the same off-white "warm" colors to mirror sunlight's hues. But this also only amplifies the harsh contrast blue-tinged CFLs and LEDs have, because many places don't use them and it's not natural for most people.

Actually to be correct, the term is color temperature... it has it's own scale: http://en.wikipedia.org/wiki/Color_temperature The image of the light bulbs on that page is a great example, too

Just a random link to partly answer your question, but it's the same story I remember. Last I heard true pure white LEDs are still very expensive compared to "approximate" white LEDs we see on shelves, ontop of which LEDs themselves are still relatively expensive compared to alternatives. Lets not even mention they haven't solved the largest hurdle, that even a large cluster of LEDs in one "bulb" has trouble matching the same amount of light emitted by a CFL or incandescent.

 

[Tharic-Nar]

Also, now is a good time to mention that a light's wattage means nothing. A 23 Watt bulb equating a 100 Watt incandescent? Doesn't mean anything at all, like trying to measure how fast a car is by it's MPG rating...

Lumens... they are the comparative numbers to check for brightness... which are rarely provided on CFLs, especially cheap ones (convenient that, huh?). A 23 Watt CFL could be 1500 or 800 lumens... but hey, who counts lumens these days...

 

[Kougar]

Technically yes, but I'm simply lazy and I assume most people will understand "100watt equivalent" to mean in terms of luminosity.

I use CFLs that are equivalent to 100 watt incandescents as I prefer the brightness, although it is possible now to get 150-300watt equivalent CFLs. In my case the bulbs are rated between 20-27 actual watts usage depending on brand, for the equivalent 100 watt incandescent. A 100 watt incandescent bulb is standardized to 1740 lumens, approximately.

I'd use 150watt equivalent CFLs except I'm pretty sure they would just burn/cook themselves out faster, even in sockets that are rated to hold 150 watt incandescent bulbs which burn much hotter than any CFL. Consumer Reports indicated most of the affordable CFLs weren't nearly as durable as the pricier models, by a rather significant margin.

 

[Grr]

I use CFLs that are equivalent to 100 watt incandescents as I prefer the brightness

I'm also in the same category.

The only thing I can say about LEDs is that to remember they are a directional light emitter. Unlike fluorescents and incandescents which emit light in all directions, LEDs emit a focused light in a single direction..

That is the biggest drawback which prevents me using LEDs. I think it may not even suffice my study/work table. Another thing is that I'm used to big -tubelights that brighten the whole space. Please share if u r comfortable using LEDs for work/study?

Thanks, Grr

 

[Psi*]

Yes. Having used the LED lamps for few months now i think they are a good replacement for the halogens which long ago replaced the incandescents.

They are comfortable to read paper or screen.

 

[Grr]

Yes. Having used the LED lamps for few months now i think they are a good replacement for the halogens which long ago replaced the incandescents.

They are comfortable to read paper or screen.

Thanks.

Would just 1 LED light suffice for a study table? I don't have any sunlight coming.

 

[Psi*]

Thanks.

Would just 1 LED light suffice for a study table? I don't have any sunlight coming.

They are little pricey. I experimented with raising that light to a 10" shelf over the desk @ 9:30 PM, and yes, I think so. The light is spread out fairly uniformly +/- couple feet or so to the best of my visual detection. A light meter would be best but that hobby disappeared some years ago. But I could easily read a book and have a few other texts laid out nearby on a desk.

 

[Grr]

They are little pricey. I experimented with raising that light to a 10" shelf over the desk @ 9:30 PM, and yes, I think so. The light is spread out fairly uniformly +/- couple feet or so to the best of my visual detection. A light meter would be best but that hobby disappeared some years ago. But I could easily read a book and have a few other texts laid out nearby on a desk.

Thanks, appreciate ur response.

I'll give it a shot.