Colour Temperature Guide
Our colour temperature guide covers the different light temperature LEDs available, giving you the information you need to purchase the right bulb for your room.
Intro
Choosing the right colour temperature for a light bulb is important as it helps create the desired atmosphere in a room. From creating a bright working environment to achieving a warm and comforting ambience, this guide explains what light bulb colour temperature is, and how to pick the best LED for your space.
What Is Colour Temperature?
Colour temperature, also called correlated colour temperature (CCT), refers to the warmth or coolness of the light emitted from a bulb. However, it does not relate to the colour of the bulb itself. Colour temperature is measured in Kelvin (K), a numerical scale between 1000K and 10,000K. The lower the number of kelvins or colour temperature, the warmer the light will be.
A warmer light will appear yellow or orange, whilst cooler lights appear bluer. LED lights come in various colour temperatures from warm white to daylight. Candlelight has a Kelvin rating of approximately 1800K for reference.
Warm White
Warm white is often used for lighting in homes, it has a kelvin rating of up to 3000K. This type of lighting creates a warm and relaxing atmosphere, making it popular in some restaurants and hotel lobbies.
Extra warm white light provides an orange and yellow toned glow and it is a great choice for creating a cosy and comforting ambience. However, it can also decrease the visibility of the environment. This may prevent you from seeing everything you need to. Therefore, extra warm white, also called soft white, is unsuitable for most working spaces or sites with safety hazards, such as a factory.
LED lights with a 2700K colour temperature are popular as they give off a similar glow to traditional halogen and incandescent bulbs.
Cool White
Cool lighting measures between 3500K-6000K. This type of light is used to create cleaner and brighter-looking rooms. This makes it a popular choice in modern homes.
This lighting also gives clearer visibility than warm white, making it ideal for use in kitchens and bathroom vanity spaces. The cooler colours are also more energising than warmer hues, making this lighting suitable for the workspace as it is thought to help encourage productivity. To learn more about the minimum health and safety requirements for workplace lighting, read HSE’s HSG38 guide. Cool white is also used for accent lighting.
However, if placed in the wrong setting, this type of lighting can make a room feel cold and sterile. Therefore, it is always wise to test cool white light bulbs in rooms alongside warmer white LEDs to see what works best, before permanent installation.
Daylight
Daylight colour temperature has a Kelvin rating between 6000K-6500K. The popular daylight bulb mimics natural light to provide a bright and clean-looking environment. This type of lighting is commonly used in work areas where concentration is required, as well as in security and display lighting.
It is important to note that this lighting is often not suitable for use in bedrooms or living rooms. This is because the blue tones of the light are harsh and unrelaxed, possibly impacting the body’s ability to create melatonin. This may affect sleep cycles.
Smart Lighting
Some LED lights have the ability to change between warm and cool light, these are called smart lights or colour-changing light bulbs. These lights are often dimmable, allowing you to adjust the lighting in a room to suit the occasion.
Replacing Incandescent And Halogen Bulbs
Incandescent and halogen light bulbs are now replaced with more energy-efficient LED alternatives. In an effort to address climate change, the UK government introduced a halogen bulb ban in September 2021, which stopped the sale of mains voltage halogen non-directional lamps. These traditional bulbs emit a warm light. When replacing them, the colour temperature may be printed on the bulb’s base, if not, it can be taken to a shop and matched with the corresponding LED colour temperature.
Colour Rendering Index
Colour rendering index or CRI is different to colour temperature. CRI measures a light source’s ability to show colours as clearly as they would be seen with natural light. Colour rendering is measured on a scale between 0 and 100. The better the CRI, the higher the value. For artwork, it is recommended to use a CRI above 90. For most everyday lighting applications, 80 is sufficient.