Ideal color temperature for indoor lighting

[Tixx]

I've had good luck with 3000k under cabinet lighting.

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[Tixx]

I'll have to find out the temp of my front porch canned led lights as they look good as well.

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[Frank W]

Depends a lot on the time of day, room and work/sleep cycle.

There are well researched body needs for different type of light depending on biorythm.

For any general day living/working conditions, plenty of light and 5000K 98CRI T8s, especially during winter months - the human circadian cycle needs daylight to function properly, hormone production depends on it.

Especially in the early morning in winter months (when there's no sunlight), nothing beats a nice bright "sun" like light for getting up and awake.
Any evening activity, especially for a few hours before getting to bed, a warm muted light is best because it prepares the body for sleep. Almost everybody who works on a computer (and usualy most uncalibrated screens are more like 7-9000K blue) into night hours can notice they have trouble getting to sleep because the body's rythm is getting confused by it.

That's just what we are accustomed to over milenia of living with natural light.

I am currently looking at Cree LMH light modules (max 95CRI 3000K, 3000lm typical or 90CRI with 4000K) for my general lighting. Would love to have a high CRI led bulb, the most I was able to find are the Ikea ones with advertised ±85CRI and 2700K)

 

[work_permit]

I voted 3000K but that's only if I was forced to choose only one color temp. For me it depends on what area of the house and even what mood is wanted. For example, for the living room, we want a warm yellow light, and there we have 2700K. For the bathroom, my wife likes a whiter light when using the mirror, so there we have 4000K.

Similar here. 2700k for "living/lounging" areas such as living room/eat in kitchen. 3000k for bathroom, work area, closets. I used to use 4500k halogens in my work area, but grew tired of it.

 

[Anders Hoveland]

Which color temperature would you say is ideal for indoor fixed lighting (assuming a fixed high CRI)?

It depends on the application.

I think it is better to use lower color temperatures in smaller rooms, and higher color temperatures in wide open spaces. And typically people prefer higher color temperatures if they are very active and moving around, while lower color temperatures if they want to feel relaxed.

It also depends very much on the person. While most people tend to prefer higher color temperatures, it might be safer to go with a lower color temperature because the people who prefer being under lower color temperature light often really do not like higher color temperatures.

I like the color of 4200-4300K, if I could pick my ideal. But at the same time, I do not think I would want to spend all day under this high of a color temperature, not more than an hour. I like the color, but it is just a little too much to be at comfort in. 3000K may be very yellowish, but I would also feel more at ease if I had to be under it all day. 3200K is a brighter white, but still comfortable, if you have ever seen the halogen spotlights in art galleries. Yes, I think I would choose 3200K if I had to work sitting at a desk all day. If I was constantly moving around, I think I would prefer a somewhat higher color temperature.

I used to use 4500k halogens in my work area, but grew tired of it.

I know what you mean. Higher color temperatures are great, but I would quickly become tired of it. It's more of an "exciting" color of light.


Just my subjective opinion, but when it comes to LED lighting, higher color temperatures tend to be a harsher on the eyes, whereas when it comes to most fluorescents, the lower color temperature ones give off a hideous quality of light. So whether I would prefer higher or lower color temperatures also depends somewhat on what type of light source it is.


One more thing to point out; I think there is an interesting pattern manifesting itself in the poll. The greatest number respondents preferred 3000K, followed by progressively by higher color temperatures. If we look at the median preference, the color temperature at which the most equal number of respondents think is too high as the ones who think it is too low, according to the poll it is 3500K.

Of course, 2700K is a little extreme, which is why the votes suddenly went down so much going from 3000 to 2700K. But still more people voted for 2700K than 5000K, which tells you 5000K is also too extreme.
It would have been interesting to see what the results of the poll if 4500K would have been an option.

I am currently looking at Cree LMH light modules (max 95CRI 3000K, 3000lm typical or 90CRI with 4000K) for my general lighting.

Sorry to change the topic, but what is really interesting about the Cree LMH 95CRI 3000K module is that they are using a separate 470nm blue diode emitter to try to increase CRI and gain a slight edge in efficiency. Cree's TrueWhite fixtures already use a ~625nm red emitter and a light mixing chamber, so it really was not a difficult thing to do to design in a separate blue emitter also.

 

[markr6]

We just built some new offices at work and I got one. They replaced the old T12 lights with two Cree ZR Series LED Troffers. Perfection! 3500K, 4000lumen with a nice dimmer switch too.

 

[broadgage]

Many professionals in the lighting industry consider that the optimum colour temperature is partly dependant on the lighting level.
In general, the greater the intensity of the light, the higher is the optimum colour temperature.

A workplace, or a home workshop, lit to 400 LUX with cool white lamps would often be considered to be "bright and efficient looking"
A bar, restaurant, or home living room lit to 20 lux with candles, oil lamps, or very warm white electric lights would often be considered to look "warm and inviting"

A low light level from cool white sources tends to most people to look "grey, sad, and cold"
A very high light level from warm white lamps tends to feel overheated, stuffy and congested.

In a domestic living room or a kitchen also used for eating in, I would if possible install two groups of lamps of differing output and colour temperature.
A relatively high light level from cool white lamps should be provided, the exact colour temperature is according to preference and availability, but at least 4000K.
A separate switch should control another group of lamps that provide a much lower light level from very warm white lamps of about 2700 K.

This is easily achieved in many rooms by use of concealed daylight fluorescent lamps that give a bright but glare free indirect light reflected from a white ceiling.
A much lower level of more decorative light may then be achieved from wall brackets or table lamps equipped with incandescent bulbs or 2700K LED lamps.

 

[gajslk]

If I had to pick a single CCT for our indoor lights, it'd be 3000K. But in my shop, I'm quite happy with 4100K. At work, we light the whole interior with 3500K. All of these are 'indoor' lighting. So, it varies, but 2700K is often starting to seem too yellow, and 5000K is always too blue. Other than that, it just depends...

Also, it depends on the prevelance of natural light. If there's none, even 2700K is OK. With lots of natural light 4100K is about right.

Couldn't have said it better. Those of us who have trouble sleeping hate lighting with blue content. If it's going to be on only in the evening, 2700, for sure.

Gordon

 

[Anders Hoveland]

A low light level from cool white sources tends to most people to look "grey, sad, and cold"
A very high light level from warm white lamps tends to feel overheated, stuffy and congested.

I wonder why this is? I know there is probably some truth to this.
If we think about human's ancient past, high light levels typically involved daytime, whereas low light levels typically involved sitting around a fire.


The color temperature of "natural daylight" can be quite variable depending on time of day and conditions. Even geographic latitude and season makes a difference. Maybe that is why Europeans often prefer warmer color temperatures.
One little fact some of you may find surprising is that the spectral distribution of natural light for a given color temperature does not quite follow the blackbody curve exactly, as the sun's light is subject to a lot of diffusion/scattering before reaching us.

I think "sunlight" is generally a warm bright 4000K. That is a ray of sun that directly comes down after being attenuated through the atmosphere. "Daylight" also includes the additional blue background from the sky, raising the color temperature to about 5000K. An overcast sky can be even higher, 6000-9000K. Moonlight is about 4200K, if anyone was wondering.

In terms of color tint, just to put this all in perspective, if I had to narrow it to a single point, I think "neutral white" would be at about 4300K. That's really much more "white" and "blah" than natural daylight.

I would if possible install two groups of lamps of differing output and colour temperature.

I agree with this also. I think it is much more interesting and pleasant if there are larger higher color temperature light sources in the room and several smaller lower color temperature lamp fixtures, 4700-4900K and 3200K would be a good combination, I think. Just using a single type of light fixture with a color temperature somewhere in the middle to me just feels too unnaturally "white".

 

[frank70]

Here's an idea for a specialty item: how about a 3-way (~800/1600/2400 or ~600/1000/1600 lumens) with two different color temperatures, say 2700 or 3000 for the low element and 4000 for the high element; when clicked to both-elements-on, it should make everybody happy. :thumbsup:

Personally, I'm a 3000 kind of guy (I must have spent a lot of time around the fire in a previous life).

 

[Anders Hoveland]

I voted for 4000K, but it really depends how I am feeling. When I want to relax and read, I prefer a 2900K bulb. 2700K is just too orange-tinted, and 3000K is starting to get just a little bright and glaring.
4500K looks like a really nice cool white, but I am not sure I would want to be working under 4500K all day. That's like a sterile laboratory, and would start to feel like an overcast sky to me after a while. You might think 3500K might be a good compromise, but actually it looks a little "dingy" in a large open room. 4000K is warm and sunny, but can still feel just a little yellowish. Above 4000K it starts to feel like a sterile medical or pharmaceutical store. 5000K and above is starting to get too bluish for comfortable indoor use, in my opinion, but at least it is more interesting than the blah neutral white.

I wish there was a switch where I could adjust the color temperature from 2800 to 4800K, depending on how I was feeling. A little like an incandescent dimming switch, but for LED.

 

[Anders Hoveland]

The Cree TrueWhite fixtures in 4000K look really good when there's also natural daylight coming into the room.
The 4000K fixture by itself feels a little too warm and yellowish, possibly slightly dingy even, but when there is daylight streaming in through a skylight the same fixture seems bright warm white (but now 'warm' in a good way) and almost soft. I have seen this in two different places.

I think the reason for this is that natural daylight coming through a skylight often tends to be a higher color temperature because much of the light is coming from the background of the sky (rather than straight from the sun). So when this light mixes with light from the 4000K LED fixtures, it helps bring the high color temperature down to a more comfortable level. The other reason is that the spectrum of natural light has a larger ratio of cyan and green-blue wavelengths. The spectra of LED tends to lack these blue-green wavelengths, and often tends to look a little too "blue"-tinted (or purple) because all the blue in its spectrum is a royal blue. So mixing in some natural light really helps average things out.

 

[Anders Hoveland]

When it comes to incandescent bulbs in my home, I am very selective, I prefer 2850-2900K. 2700K just does not look right and 3000K is a little bright for comfortable bedroom/reading use every evening. In the U.S. I was a really big fan of the 100 Watt 750 hour bulbs, and some 2000 hour halogen bulbs (but it really depends which brand though because some of these halogens had an annoying slightly pinkish tint, for reasons I can't get into here). At 220v outlet supply, I like the color temperature of the light from the Osram Eco Halogen (70 watt, 2000 hours).


You know, I have been thinking... 3500K just looks a little unnatural. 3000K looks "natural" to me (at least when it's halogen or LED) and 4000K looks like a natural white colored light. But when the color temperature is right in the middle, it just does not look right. It seems too yellowish and dingy. Neither warm and comfortable, nor bright and sunny. Is it just me?

 

[SemiMan]

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[alpg88]

i like warm halogen light, i replaced halogens in my bathroom for 9 xml s6 bin 90+ cree, 2900k iirc, if i did not know, i would not tell a difference betwen old halogens and new leds as far as color temp goes.

 

[dfemmert]

I was just doing some searching to help me choose between neutral and cool on what will probably be my next purchase, an Eagle Eyes A6. I saw it At Banggood for $20. and then checked Amazon and they have it for $44. + $7. more for shipping. I think I read a review on it here or on another forum as well earlier which has me thinking it may be worth a few weeks wait to get one from China.
Getting back on point, I just looked at this site that include some good indoor photo comparisons using warm vs cool light.
http://tombuildsstuff.blogspot.com/2015/02/choosing-daylight-or-warm-color-bulbs.html

 

[broadgage]

If talking about the color temperature of incandescent lamps (including halogen) one should be aware that variations in supply voltage can noticeably affect color temperature.
Running a 120 volt lamp on an actual voltage of 110 volts will noticeably reduce both the colour temperature and the output.
In the USA the actual voltage supplied by most utilities is between 95% and 105% of the nominal. That is from 114 volts up to 126 volts AT THE SERVICE, the voltage at the point of use can be several percent less due to voltage drop within the consumers premises.
In many other countries the variations are greater.

 

[orbital]

+

3000K is excellent


4000K is ok for outdoors, but inside it starts to look too cold & creates harsh shadows

 

[jmoyat]

+

3000K is excellent

+1 for 3000k! Oh and dimmable...

 

[SemiMan]

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