Colour temperature is a key feature of an LED light which is often ignored.
Most people think only about the wattage of the LED light. The wattage dictates how much power it will draw and therefore how much you will pay in electricity.
Customers may also consider the look of the LED light fitting. In an office environment, you obviously want the LED lights to fit in nicely with the existing decor.
However, colour temperature is also vital.
Colour temperature is basically how ‘warm’ or ‘cold’ the light coming out of the fitting feels.
Think back to the days of 100W tungsten light bulbs. They were the ones that gave off a very orange/yellow glow and lots of heat. This orange or yellow glow meant they had a very low colour temperature.
Now consider a trip into your local, large supermarket. Very likely, the lights will give off a much less yellow colour than the old tungsten bulbs. The colour will appear ‘whiter’ and ‘cooler’. These lights have a higher colour temperature.
Getting technical now, colour temperature is measured in degrees Kelvin (K) and indicates how the light will appear to the observer.
For example, a colour temperature of 2000K will appear ‘warmer’ (think evening sun) than the ‘cooler’ 5000K (think mid-day sun). Cooler colour temperatures have more ‘blue’ in them.
An LED that emits light at a colour temperature of 5500K to 6000K, is giving out a very ‘white’ light. In other words, there is no colour tint to the light. This colour temperature is ideal, for example, for printers who need to evaluate colours accurately. There are many commercial advantages to getting colour temperature right.
Don’t get confused: so-called ‘warm’ colour temperatures have lower values in degrees Kelvin (K). ‘Cool’ colour temperatures have higher values in Kelvin. It sounds like it’s the wrong way around.
Key point: colour temperature has nothing to do with heat. It’s all about the colour.
If you work in an office, you will probably have a ceiling grid above you with square or rectangular lights. What colour temperature should these lights be?
LED ceiling panel lights are generally in the range of 4000K to 6000K. As we have seen, 4000K is warmer (it has more yellow); 6000K is cooler (it has more blue).
Light with blue in it signals to the brain to stay awake. Blue light is saying “It’s day time – get some work done.”
Light with yellow in it signals to the brain to start thinking about sleep. Yellow light is saying “The day’s coming to an end – start winding down.”
So, to stay alert during the working day, it’s probably best to have lighting in the 5000K to 6000K range.
Having said that, some people find 4000K light more friendly and welcoming. They would rather work in a cosy environment than one that feels like a hospital.
To help customers appreciate the difference between 4000K and 6000K before they commit to a project, it is best to install fittings of both colour temperatures in a couple of areas and let them decide which one they prefer.
For a comprehensive analysis of colour temperature and the science behind it, please see this Wikipedia page.
