Colour Temperature - How to Choose The Best Colour Light
Asking 'Which colour temperature is best?' is a bit like asking 'What colour should I paint my wall?'
There is no right or wrong answer. The right colour temperature comes down to personal preference, the room you are lighting, and what you're used to.
There are so many things to consider when purchasing lighting. So colour temperature may not be at the top of your list of priorities. Nevertheless, the colour temperature of lights has a noticeable effect on the feel of a space. And if you have to pick one, it’s good to know what it's all about.
Here are a few tips to help you make the best choice.
Colour Temperature Scale
First up, let's review the colour temperature scale. For lighting, colour temperature ranges from 2000K candlelight through to 6500K cool white. In between, there are a wide range of colour codes and an even wider range of words used to describe them.
Note: the technical term is Correlated Colour Temperature (CCT). For this reason, you will often see it labelled as CCT in lighting specifications.
Colour temperature chart and examples.
|1700K||Match flame, low-pressure sodium lamps (orange streetlights)|
|1850K||A candle flame, sunset & sunrise|
|2400K||Standard incandescent or filament lamps|
|2700K||Soft white compact fluorescent and LED lamps|
|3000K||Warm white compact fluorescent and LED globes|
Neutral white or cool white fluorescent tubes
|5500 – 6000K||Vertical daylight, electronic flash|
|6500K||Cool daylight fluorescent tubes, overcast|
|Note: terminology and actual correlated colour temperature vary extensively. Examples modified from Wikipedia.|
Colour Temperature & Heat Temperature
The way we describe colour temperature is the opposite to how we talk about heat temperature.
The higher the colour temperature on the Kelvin Scale, the 'cooler' the colour. The lower the colour temperature, the 'warmer' the colour.
As a side note, LED lights produce far less waste heat than other lights, regardless of the colour code.
The Colour Temperature Numbers Are What Matter Most
Colour temperature is expressed as a four-digit number in the unit kelvin, using the symbol K. For example, 2700K, 3000K, 4000K or 6500K.
Lighting manufacturers also like to use words such as warm white, cool white or daylight to describe these colours.
As there is no industry standard for these phrases, it's important not to rely on them too heavily. One brand's 5000K could be described as 'daylight', whereas another brand could refer to the same item as 'cool white'.
There is even some variation within one brand. For example, we have noticed that Philips describes 4000K bulbs as 'cool white'. Yet the same colour code in fixtures is routinely described as 'neutral white'.
Therefore, if you’re trying to match or replace a specific colour temperature, it's best to ignore the descriptive words and look at the K number. The same rule applies if you’re comparing two different products.
The International Colour Temperature Code
Be aware that colour temperature is often specified as a code like 830, 840 or 965. This is often the case with LED or Fluro Tubes. These codes combine two lighting specifications into one: colour rendition and colour temperature.
The first number refers to colour rendition:
- 8 = colour rendering index Ra 80 – 89
- 9 = colour rendering index Ra 90 – 100
The second and third numbers refer to colour temperature, for example:
- 27 = 2700K
- 30 = 3000K
- 40 = 4000K
- 50 = 5000K
- 65 = 6500K
An example colour temperature code on an LED Fluro Tube.
The Difference Between 'Warm' and 'Cool' Lights
Generally, 'warm white' is atmospheric and 'cool white' is practical.
The choice of colour temperature can be used to create certain moods in your space. This is similar to how certain colours have cultural connotations (e.g. red = passion, blue = calm).
Lower colour temperatures are considered 'warm' because they remind us of fire or candlelight. Warm white colour temperatures can be used to create a cosy atmosphere in bedrooms, cafes and restaurants. This colour temperature is also described as soft white.
These vintage style filament LED bulbs are perfect for cafe lighting. They have a colour temperature of 2000K to 2700K.
Higher colour temperatures tend towards blue and are considered 'cool'. Actual daylight is about 5500K. So if you want to recreate the feeling of natural light, go for a higher colour temperature.
Higher colour temperatures are generally perceived as brighter. They’re great for work areas like kitchens and offices. (Note: if you’re looking for more brightness - the specification to check is lumens, not colour temperature.)
A downside to high colour temperatures is that they can appear stark, harsh or sterile. For example, hospitals and 7-Eleven stores tend to use high colour temperatures.
This 4000K LED panel (to replace fluorescent fittings) is used in offices.
Colour Temperature Consistency is Key
Colour temperature discrepancies are more obvious when two bulbs of different colours are placed next to each other. Mismatched lighting can seem incongruous. So whatever you choose, try to keep the colour consistent within a space. For example, all the downlights in one ceiling should match.
This may create a problem in open plan living, where the kitchen and living areas are in the same room. A cooler colour like 4000K might work in the kitchen, but could seem too stark for the lounge. Likewise, a warm colour like 2700K might be great for the living area, but not practical enough for working in the kitchen. In this case, meeting in the middle at 3000K is a good compromise and keeps the light consistent throughout the space.
That’s probably why 3000K is the highest selling colour temperature for our LED downlights. Its versatility makes it a popular choice.
That being said, don’t be afraid to use different colour temperatures in separate rooms if you need to. You can also have one colour temperature for ceiling lights, and another for floor and table lamps. This allows you to switch between the two modes of lighting for different occasions.
When in doubt, stick with what you are used to
If you're upgrading an old light to LED, ask yourself, what colour are you replacing? Do you like what is there? If so, then there’s no harm in trying to match it. Check the small print on the bulbs or tubes that you already own to see what their colour temperature is.
Most LED retrofits already have colour temperature options that match old globes. If you can’t find an exact match, don’t worry, near enough should be good enough.
Can’t decide? Try a 'tri colour' light fitting
Some LED lights can even change their colour temperature. Two examples are:
- Tri colour light fittings. These have a switch on the back of them so you can change the colour temperature post-purchase. These are sometimes specified as 3CCT.
- Smart or wifi light bulbs. These light bulbs are controlled via an App on your phone. They are described as 'tunable white' or 'RGB' for full-colour control.