At this time of the year when the days are short, and a warm and welcoming home environment feels all the more important. A crucial aspect of creating this cosy ambience is the interior lighting scheme. This is not just a matter of selecting and arranging lamps and fixtures, but also of understanding the role of colour temperature.

Here’s a look at the fundamentals of colour temperature, and how to harness it to create the perfect mood in every room in your house.

The science of colour temperature

Colour temperature is a way of describing the appearance of different hues of light produced by a light bulb. It is measured in Kelvins (K) and the scale is ‘warm’ at one end of the spectrum and ‘cool’ at the other end. The warmest tones have an amber appearance, while the coolest tones are bright blue. 

In terms of bulb light, The Kelvin scale ranges from 2000K (the warmest colours) to 6500K (the coolest colours). The colour temperature of the bulb should not be confused with brightness, which is measured in lumens or watts. It relates only to the colour of the light.  

The red and amber light that is used for fixtures such as ornamental fires and electric candles and suchlike will have a range of 800-2700K, Halogen lamps are usually in the middle of the range with a yellowish light of around 2700K -3500K, and the coolest LED bulbs emit a white or blue light with a value of between 3500K and 5000K.

Which colour temperature should you choose?

If you want to create a warm and cosy atmosphere in a space where you tend to relax and wind down at the end of the day, such as the living room or bedroom, look for bulbs that emit a soft amber or yellowish glow at the warmer end of the spectrum, typically (2000-3000K).

This warm light naturally mimics the body’s circadian rhythm as we prepare to rest and relax, so it will help you mentally switch off at the end of the day and get a good night’s sleep. 

If you desire a neutral light for a space such as a bathroom or hallway, where you want a good balance between clarity and a comfortable ambience, then choose white bulbs in the 3000-4000K range. You may wish to use these bulbs in your kitchen or office as well, perhaps for a designer desk lamp.

If you prefer a really crisp cool light that mimics bright daylight, then look for cool white bulbs in the 4000-5000K range. These bulbs are suitable for rooms where you carry out tasks such as cooking or reading, or where there is no natural light source from a window.

Remember you can always layer your task lighting with accent and ambient lighting within the same room if you use it for different purposes, and want to create a variety of atmospheres. 

For the maximum bright cool light, LED bulbs of 5000K or more are available. These tend to be used in larger commercial spaces such as offices, shops, and warehouses.