Image displaying colour temperature

Have you ever changed a blown lightbulb and noticed that its replacement does not match the colour of light that it gives off? What once was a nice warm glow has now become a harsh white light and all of the sudden the room no longer has the same ambience and feeling. Or when your white lit, modern kitchen now has a yellow tone that doesn’t accurately highlight the area! It’s because there is a whole colour spectrum of lighting based on colour temperature.

It’s understanding this temperature that makes it easier to choose a light that will give off the look and feel that you want in your room. But why is it that some bulbs glow a bright white, while others emit a warm orange?

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What Is Colour Temperature?

The basic explanation of colour temperature is this:

Imagine that you have a black, metal object and you heat it up. As it begins to warm up it starts to glow a different colour – first red and orange, and then yellow and then white. But as the object reaches its hottest temperature, it will start to glow various shades of blue.

Colour temperature is simply a way to describe the appearance of the light produced by the bulb. It is measured in degrees Kelvin on a scale ranging from about 1,000K to 10,000K and does not directly correlate to the temperature of the bulb itself. ‘Warm white’ does not mean a higher temperature, instead it just means a warmer looking white, i.e. yellow white. Much the same, ‘cool white’ does not mean a lower temperature, but rather cooler looking white, or blue white. In fact, cool white is higher on the temperature Kelvin scale than ‘warm white’. The colour temperature of the bulb is assigned using Correlated Colour Temperature (CCT) and lets us know what the look and feel of the light will be before we even switch it on.

Kelvin Colour Temperature
An example of how colour temperature produces different shades of white light.

How Can Colour Temperature Help?

At the lower end of the scale your lighting is generally around 2,000K to 3,000K. This is known as your ‘warm white’ and gives off a yellow, orange tone. Generally this type of lighting is found in your typical incandescent and halogen bulbs and because of the warmth of light that it gives off, it creates a relaxing and inviting ambience in the room. Therefore, they are best in rooms that are used to unwind such as the lounge area, bedroom and dining area (for more information on how lighting affects your mood, productivity, creativeness and hunger read our blog here).

Lighting that is around 3,100K to 4,500K is generally emitted by your whiter fluorescent bulbs. The white that is given off is a much brighter, cooler shade of white which tends to make the room feel much brighter and vibrant and a lot less relaxing. Whiter, cooler lights improve our ability to see contrasts better and it is for this reason that they make the perfect choice for rooms where alertness and high attention to detail is needed such as in the kitchen, bathroom and office space.

When lighting reaches 4,600K to 6,500K, and slightly above, is when it begins to mimic pure daylight and has a distinct, white/blue tint. The lighting that is emitted by these bulbs is extremely crisp and bright and can sometimes be much too harsh for household rooms. Instead, these bulbs are perfect for display areas, security lighting and garages when an intense amount of light is needed.


When choosing lighting for the rooms in your home, think about what those rooms are going to be used for. Are you installing new lights in your lounge area or bedroom? ‘Warm white’ lighting around 2,000K to 3,000K is best in these areas, to keep you relaxed and comfortable. Or maybe you are looking at lights for your kitchen or bathroom? You will need much whiter lighting for this so  bulbs that have 3,100K to 4,500K displayed are perfect! Keep those lights shining bright in your garage with bulbs between 4,60K and 6,500K!

By taking a look at the temperature Kelvin of the bulbs and by understanding what these numbers mean, you are guaranteed to find the perfect lighting for your home every time.

For more information on lighting in the home, or to have lighting installed, call Green Efficient Living today on (08) 8297 3422.

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