Nichia Develops 60 Lumen Per Watt White LED

[ddrueding]

The sun is different colors throughout the day and depending on cloud cover, it is fairly yellow at sunset and sunrise. However, during the day or when it's overcast the sun is between 5500-6500k.

Thanks for that; saved me from the work. Except to note that even at sunrise and sunset, the sun is hardly ever below 4500k. Anything below that is yellow, and you are letting your eyes play tricks on you.

 

[LunarMist]

4100K appears fairly neutral in an office. Sunrises are 3500 or even lower sometimes. One often overlooked issue is that the perception of neutrality varies with intensity. In low light such as indoors a lower color temperature looks cooler than at high brightness levels such as outdoors. There are also differences in individual photoreceptors and changes with age.

 

[time]

In response to Ddrueding:

AFAIK that's not correct. The sun is well below 4500K at sunrise and sunset; it seems it doesn't pass that for at least two hours after/before. Eg: http://www.apogeephoto.com/july2004/jaltengarten7_2004.shtml

To be pedantic, the actual Sun color temperature is about 5400K; the higher temperatures are due to filtering and reflection, eg. from the sky or when it's overcast. IMO, any artificial light over 6000K is going to have much the same effect as an overcast sky.

I think one of the reasons that people have learned to prefer warm white fluorescents may be that poor color rendition becomes more obvious at higher color temperatures. So crappy CFLs (and maybe LEDs?) look better at 2700-3000K than at 4000-5000K.

Also, the abbreviation for Kelvin is a capital K - lower case is short for kilo, as in thousand.

 

[ddrueding]

Interesting, that is different data than I had seen elsewhere. I'm sure lunar has the equipment to measure such things in the field, and will take his word for it.

And I'll cede to all your pedantry

 

[LunarMist]

In the old days we used the Minolta color meters. I think they ceased production years ago when digital cameras became popular.

I'm sure you can buy some decent meters from the scintifuc supply shops.

 

[sechs]

The fluorescent lighting in the office area I work in is 'Warm White'. We had the 'Cool White' lamps replaced about 12 years ago.
The only CFL lamps my wife lets me install are in the yellow range.
The blue hue lights look very un-natural to me.

I'm guessing that this is because you are comparing them to your sickly yellow ones.

Your eye and brain will automatically white balance whatever light you are seeing. All of my CFLs are 5500K or higher, and when one of those is next to a 6500K lamp, I can tell how much yellower the the cooler one is. After you've used a particular color of light for a while, you get used to it.

The fact of the matter is that those "warm" white lights don't come close to reflecting the actual light one sees during the day.

 

[sechs]

4100K appears fairly neutral in an office.

Basically, you're saying that daylight is not neutral in an office. It's too cool.

 

[LunarMist]

Basically, you're saying that daylight is not neutral in an office. It's too cool.

To my eyes, it is awful that way. I know some people are prescribed the bluebo lights for SAD, but

 

[time]

Basically, you're saying that daylight is not neutral in an office. It's too cool.

Apart from the times when the sun is streaming directly through a window, all interior light of external origin is reflected and shadows are highly diffused. The color varies widely according to what it's been reflected off, but I certainly wouldn't count on the color temperature being 5500K or 6500K. Whereas most office lighting schemes concentrate on projecting the light directly (which of course is another problem in itself).

 

[Bozo]

According to this, the sun is white. It's color gets screwed up in our atmosphere. I stand corrected.

 

[Bozo]

[h=2]Philips’ new 100W-equivalent LED bulb runs on just 23W.[/h]Seems I have some 100W CFL bulbs that use about the same??? :scratch:

 

[Newtun]

Philips’ new 100W-equivalent LED bulb runs on just 23W.

Seems I have some 100W CFL bulbs that use about the same??? :scratch:

Strange, it acts like a link - hovering over it turns it red underscored. But it don't link and the cursor doesn't turn into a hand. (FF 12).

It does in my quote, but it links to "itself". Wonder if it's because it's bolded.

 

[time]

Bozo mixed up the tag somehow: there's no URL.

I agree that apart from extended life (presumably 25000 hours), it's not obvious how this improves on a 23W CFL. In fact, with 2700K the only color temperature option and a far higher price, it seems like a retrograde step.

 

[LunarMist]

Instant full brightness would be worthwhile in many applications.

 

[time]

For a 100W equivalent bulb ... such as?

 

[Santilli]

40-60W LED at Costco, about 6-10W 3 for 20 dollars, IIRC.

 

[Bozo]

I'll try it again. Phillips LED

 

[sechs]

Apart from the times when the sun is streaming directly through a window, all interior light of external origin is reflected and shadows are highly diffused. The color varies widely according to what it's been reflected off, but I certainly wouldn't count on the color temperature being 5500K or 6500K. Whereas most office lighting schemes concentrate on projecting the light directly (which of course is another problem in itself).

I will just point out that, unless you're looking directly at your lights for some reason, then all of the light that you see in an office is reflected and has interacted with the internals of the space in some way.

My point was that sun light really should be the benchmark, and daylight should always seem fine in any non-color-rendition-sensitive situation.

 

[Santilli]

Great. Now you have to put your light bulbs in your will.

 

[LunarMist]

2700K?

 

[time]

In a commercial situation such as an office, most of the light I 'see' is direct illumination of the objects I'm looking at, such as a piece of paper on the desk. The only significant reflection is from the object to my eyes, which of course is how we see.

I'm suggesting that natural light is highly indirect, but commercial artificial lighting tends to be direct. Given the chance, I believe most people prefer two-stage lighting, where there is a decent level of fully indirect lighting complemented by highlighting of certain elements in the environment as needed (task lighting).

But I still don't believe you end up with something as yellow as 2700K!

 

[LunarMist]

2700K looks good in the toilet, maybe.

 

[Howell]

2700K looks good in the toilet, maybe.

Literally. Maybe.

You have been eliminated.

 

[LunarMist]

Well I should have salted Kitchen and Bath.

 

[LiamC]

Is 760-860 lumens in an MR16 replacement, @ 15/18W (LED/system) good, bad or indifferent? Ditto a CRI of 85? I would like to replace a lot of 50W halogen downlights. What should I be looking for, and are there gotchas if you want to make them dimmable. We are about to embark on renovations, and I really want to think about lighting solutions, for lounge rooms and bedrooms, and not just go with a single central fixture per room.

http://www.ledlighting.com.au/EVO50.html

 

[LunarMist]

Is 760-860 lumens in an MR16 replacement, @ 15/18W (LED/system) good, bad or indifferent? Ditto a CRI of 85? I would like to replace a lot of 50W halogen downlights. What should I be looking for, and are there gotchas if you want to make them dimmable. We are about to embark on renovations, and I really want to think about lighting solutions, for lounge rooms and bedrooms, and not just go with a single central fixture per room.

http://www.ledlighting.com.au/EVO50.html

It looks like they might be fine if you can live with the limited color temp and abeam anlge options. The Halogen are usually about 950 lumens, so the overall output should be OK. Can you buy a couple for comparison with your curent setup? That's the only way to be sure.

 

[Santilli]

New PG&E bill. 20.00 dollars! WTF?

How can moving to LED and MFL's make THAT much of a difference? When the house was all MFL the cost was about 50.00. Figured it didn't make that much of a difference.

I'm suspecting that the power draw for MFL starting up is a problem, since I rarely leave the lights on for long. Perhaps the LED's draw far less on startup, and therefore are a MUCH better
solution for a household that turns lights on and off, rather then leaving them on all the time?

 

[ddrueding]

Another thing to think about is that MFLs hate power cycling. They will kill the bulb faster than leaving it on in many instances. LEDs don't care.

 

[sechs]

I wouldn't really be concerned about on-off cycling in the life of the light.

I turn my CFLs on and off when entering or exiting a room, and they usually last at least five years. I've even put one in the refrigerator, which is terribly bad.

My last CFL that failed was almost ten years old, and it's the first one that has failed on me due to a failure of the electrodes, rather than the ballast.

 

[sechs]

I swear, I only hit the button once....

 

[Santilli]

I jumped on the CFL bandwagon at the start. That whole batch failed, within 2 years.

The new ones are far cheaper, seem to use less energy, and combined with the LED's have dropped my energy bill by 60%, or more.

 

[Stereodude]

I wonder if the Switch Bulb folks will ever actually sell their bulbs. Or, maybe they're content to just push press releases and sell vapor.

 

[sechs]

It looks like they've worked around the geometry problem by using a piece of glass. That makes me worry about heat rejection.

 

[LunarMist]

I wouldn't really be concerned about on-off cycling in the life of the light.

I turn my CFLs on and off when entering or exiting a room, and they usually last at least five years. I've even put one in the refrigerator, which is terribly bad.

My last CFL that failed was almost ten years old, and it's the first one that has failed on me due to a failure of the electrodes, rather than the ballast.

Mine don't seem o last that long. The ones in the dining fixture last about five years and are on about 80-100 hours per week. The lights in the west toilet are on around a tenth of that time, but cycled frequently. Those lights only last about two years. There is one light on 24/7 that lasts about three years.

 

[LunarMist]

It looks like they've worked around the geometry problem by using a piece of glass. That makes me worry about heat rejection.

It looks like 12 small emitters spaced around the perimeter. Won't that produce a worse illumination pattern than the lamps with a small number of large phosphor areas?

 

[time]

The ones in the dining fixture last about five years and are on about 80-100 hours per week ... There is one light on 24/7 that lasts about three years.

That works out to 21,000-26,000 hours! Which brand and models are you using? That's fantastic!

 

[LunarMist]

I don't know the exact details, but it is one of the dimmer (40W replacement) lamps. It is just the point that the same lights in the toilet don't last nearly as long when typically illuminated for only a few minutes each time.

Now I have three types of LEDs in several rooms for comparisons. None are bright enough for a single-lamp fixture yet, but I guess there will be brighter lamps soon.

 

[sechs]

Mine don't seem o last that long. The ones in the dining fixture last about five years and are on about 80-100 hours per week. The lights in the west toilet are on around a tenth of that time, but cycled frequently. Those lights only last about two years. There is one light on 24/7 that lasts about three years.

Generally, five years is about what consumer CFLs are rated to last under "normal" conditions. One must keep in mind that, although CFLs are getting cheaper and better, those two things don't necessarily go together.

I don't usually put new CFLs in bathrooms, as other conditions there tend to reduce their lives.

 

[sechs]

It looks like 12 small emitters spaced around the perimeter. Won't that produce a worse illumination pattern than the lamps with a small number of large phosphor areas?

I'm not sure what you're asking, but the suitability of an illumination pattern depends largely on the application.

 

[sechs]

Now I have three types of LEDs in several rooms for comparisons. None are bright enough for a single-lamp fixture yet, but I guess there will be brighter lamps soon.

I just got some GU10 LED lights and am quite impressed about their performance versus the halogens that they replaced.