Colour Temperature: what’s the difference between warm white, cool white and daylight bulb?

Lighting in a room isn’t just part of the décor, it can have an impact on everything from your sleeping pattern to your concentration levels.

Choosing your new ceiling light, table lamp or exterior fixture is just the first step towards perfectly lighting your home. The next, and arguably most important, part is choosing the right lightbulb and light colour.

Lightbulbs and integrated light fittings come in all shapes, sizes and wattages – but did you know they have different colour temperatures too? The most popular choices are warm white, cool white and daylight. Each colour serves its own purpose, and you’ll find that different rooms and lights suit different colours.

Today we’re taking an in depth look at each light colour, and giving you an idea of where they will work best in your home.

To make your lives a little easier when shopping for your new bulbs, we thought we should explain some of the science behind them first. So before we get started on the styling, let’s get technical for a minute.

The light produced from a bulb is dependent on three things:

1. Lumen output
2. Colour rendering
3. Colour temperature.

Lumen output

Many people are familiar with the lumen output as this determines the brightness of a bulb. In simple terms, lumens are a measure of the total amount of visible light to the human eye from a light source.

So, the higher the lumen rating, the brighter your light will appear. Don’t mistake this for wattage though, as that determines the energy of the bulb, not necessarily the brightness.

The number of lumens you’ll need will entirely depend on the type of bulb you’re buying, the fixture it’s being used for, and the size and shape of the room where it will live. There is no right answer for this, as only you can decide how bright you want your bulbs.

The Colour Rendering Index

Colour rendering is the ability of a light source to accurately display colour. It is measured on a scale of Ra 0–100. The higher the Ra number, the more accurately represented the object being illuminated will be.

Put simply, if you choose a lightbulb with a high Ra number, you’ll increase your ability to see the true colour of the objects in your room. 

For workplace lighting, the European Union’s standards dictate the lighting needs to be a minimum Ra 80. Of course, there are no such standards for the lighting in your own home, but it’s certainly worth considering when choosing your lightbulbs. 

The Kelvin Scale

The colour temperature of a bulb is measured in Kelvins. The Kelvin Scale runs in the opposite direction to the temperature scale – so the warmer the glow colour, the lower the rating.

It’s really important when replacing a bulb to take note of the Kelvins as well as the brightness and the wattage. If you don’t, you could end up with mismatched bulbs sitting next to each other on the ceiling or in a multi arm fixture. This won’t look right and you won’t be utilising your lighting to the best of its ability.

If you’re happy with the existing lighting effect of your bulbs, then the best way to replace them is to take the old one with you to the shop. This way, you can match up the Kelvins exactly to ensure you’re getting the right thing.

Choosing the right colour for the right room

Let’s take a look at the rooms and fittings that each colour lightbulb works best for. 

We go into a more detailed look into how we recommend styling your home further down this page.

Choosing a colour temperature for each room in your home:

Warm white: 2,000 – 3,000K

Cozy, calm, relaxing, inviting and intimate.

• Bedrooms
• Dining Rooms
• Living Rooms

Cool white: 3,100 – 4,500K

Bright, vibrant. Keeps you alert.

• Offices
• Bathrooms
• Kitchen
• Basements

Daylight: 4,600 – 6,500K

Crisp and invigorating. Mimics sunlight.

• Garages
• Security lights

Choosing a colour temperature for different light fittings:

Warm white: 2,000 – 3,000K

• Chandeliers
• Double arm wall lights
• Up and down wall lights
• Table lamps
• Festoon and string lights

Cool white: 3,100 – 4,500K

• Rise and fall ceiling pendants
• Desk lamps
• Picture lights
• Track and spot lights
• Under cabinet lights
• Recessed downlights

Daylight: 4,600 – 6,500K

• Wall mirrors
• LED Battens
• Floodlights

Now you know how to identify the right lightbulbs, and which room to use them in, let’s talk a little about how to style them.

Styling warm white lightbulbs

Warm white lightbulbs are soft with a yellow tone. Their warmth invites relaxation, so they are ideal for creating a cosy and comfortable atmosphere in rooms where you want to chill out by yourself, or spend quality time with friends and family.

Many people choose this warm white colour lightbulbs for their living room, bedroom or dining room where everyone spends the most time together. They work particularly well in table or floor lamps as well, adding some interest to the room whilst maintaining that important relaxing atmosphere.

When you’re choosing the décor style for your home, it’s a good idea to consider the warmth of the lighting you will be using. In the rooms where you’ll choose warm white lightbulbs, think about how you can take that theme across the space, utilising wall colours and furniture.

Scandinavian design suits warmth well due to the famous hygge lifestyle. Think cosy blankets, warm-toned neutral walls and simple wooden furniture. Be careful when working with crisp white walls though, as they can look very different under the light of a warm white lightbulb.

Choosing your fixtures

It’s up to you where you want to use your warm lightbulbs, but certain fixtures do work best for optimising the colour temperature. We’ve listed some of our favourites below that we think suit the warmth especially well.

• Chandeliers. If you want to make a style statement in your dining room or bedroom, a chandelier is a good choice. Whether you choose a contemporary style or a classic vintage look, the warm white lightbulbs will create the perfect ambience for your space.
• Double arm wall lights. A nice option for bedside lighting if you don’t want to use up valuable table space, double arm wall lights are perfectly suited to warm bulbs. If you choose an antique style like the Edit Chateau, the warmth of the glow will really amplify the candlelight effect.
• Table lamps. Available in all shapes and sizes, table lamps are a versatile piece for almost any room in your home. This smoked glass lamp would look beautiful with a warm bulb in a dining room, while this quirky giraffe lamp would suit an eccentric living space.
• String lights. Brighten up your outdoor space with a string of warm white lights. Ideal for garden parties or just relaxing outside with a glass of wine, a warm glow of light is the perfect finishing touch.

Styling cool white lightbulbs

The fresh and clear glow of a cool white lightbulb makes them brighter and more focused. A popular choice for use in bathrooms, kitchens and workspaces – cool bulbs work best in rooms where you need to concentrate a little more.

Cooler colour temperatures have been shown to help us stay alert and motivated, so a cool bulb in the bathroom could perk you up in the morning. Similarly, whilst you’re cooking dinner at the end of a long day, a cool light could help you to concentrate better on what you’re doing. 

Cool white lightbulbs are often used for task lighting as well, and there’s nothing stopping you having a cool white desk lamp in a room that otherwise uses warm bulbs. Don’t be afraid to mix and match your bulbs to suit your needs.

As cooler colour temperatures are closer to natural light, you can style your room without worrying too much that it will look different when you switch the lights on. Many people consider cool white lighting to be the more contemporary choice, so a modern and sleek style décor could work particularly well.

Choosing your fixtures

In the same way that warm bulbs suit certain styles, cool lightbulbs have their own optimal fixtures as well. We’ve outlined some of the ways you could use cool white bulbs in your home.

• Rise and fall pendants. With the ability to adjust the height of these ceiling pendants, the rise and fall style works perfectly for task lighting over countertops or work surfaces. A simple design suits the cool white bulb, while working with a range of décor styles.
• Desk lamps. To aid concentration and focus, it’s a good idea to use a cool bulb in your desk lamp. A sleek and minimal style suits the cooler light temperature well, whilst still looking stylish.
• Picture lights. If you require a fixture to light up a piece of art or a display, then a slimline picture light could work for you. You should consider a cool white bulb for this, as warmer bulbs might distort the colours of whatever it is you’re showcasing. A lot of our picture lights have integrated cool white bulbs, meaning you don’t need to worry about finding the right bulb.
• Under cabinet lights. If you need a little more light in the kitchen, under cabinet lighting with cool white bulbs is an easy option to brighten up your work surfaces. This makes it easier to see areas where food is prepared without losing the warm social lighting of your kitchen dining area.

Styling daylight lightbulbs

If you’re looking to create a natural effect, daylight bulbs might be right for you. They mimic the natural light emitted from the sun and can be a useful tool for a number of situations – especially for offices or rooms with no windows or very little natural light.

These bulbs are the highest on the Kelvin scale, and they can totally transform a room from dark and dingy into bright and colourful with just the flick of a switch.

They can also be very helpful for people who suffer from Seasonal Affective Disorder (SAD), as they can be affected by a lack of natural light during the long winter months. The addition of a daylight bulb can inject a little more brightness into your home, helping to boost your energy and your mood.

Choosing your fixtures

Daylight bulbs don’t have to be ugly. They can be incorporated into most fixture styles, so you can use them across any room you choose. They are particularly effective for bathrooms with no windows, or even basements so you can fully utilise the room.

While daylight bulbs are traditionally used in offices or garages, you can incorporate them into your home as well. We’ve got a few ideas up our sleeve for choosing the best fixtures for a daylight bulb.

• Wall mirrors. Whether you have a dressing table area, or you use a mirror light in your bathroom – using daylight bulbs is a great idea to ensure you can really see what you’re doing during your make-up and pampering sessions.
• Reading lights. While some people like to curl up with a novel in bed next to the glow of a warm lamp, there are others who prefer a brighter light for this task. Whether you’re reading a report at your desk, or a magazine on the sofa, you might want to consider a daylight bulb for your reading light.
• Downlights. For rooms that require a little more practicality, downlights can be tucked away into the ceiling so you won’t even notice them. A daylight bulb will help to fill the room with natural light, making it even more useful. 
• Batten. If you want to brighten up your workshop or garage so you can work in there at all hours, a weatherproof batten with a daylight bulb is a good option. The colour temperature will help you to see exactly what you’re doing, no matter the time of day. 

Overall, it’s safe to say that colour temperature plays a big part in getting the lighting right for your home. The difference between a warm glow bulb and a bright daylight bulb is huge, and can make a big impact on the usability and optimisation of each room.

We hope you’ve found this article helpful, and have learned a little more about how the lighting in your home can help you to concentrate and focus when you need to, as well as relax and unwind at the end of the day.

For more information, view our full range of lightbulbs on our website.