LED lighting comes in a variety of colour temperatures – ranging from soft and warm yellow-ish tones, to cool daylight-like blue tones. Choosing the correct colour temperature can alter how a room looks, feels and functions.
Colour temperature is measured in Kelvin (K). This guide explains the Kelvin scale in simple terms, recommends suitable temperatures for different rooms in your home and offers practical tips for mixing colours, reading product labels and avoiding common mistakes.
What is colour temperature and how is it measured?
Colour temperature describes the appearance of light produced by a lamp and is expressed in Kelvin, written as K. Lower Kelvin values produce warm, yellow-orange light while higher values produce cooler, bluer light. Typical groupings are:
- 2200–2700 K: extra warm white, very cosy and amber-toned
- 2700–3000 K: warm white, commonly used for living rooms and bedrooms
- 3500–4100 K: neutral white, good for balanced task lighting
- 5000–6500 K: cool white or daylight, crisp and bright for workspaces
Two other important specifications are lumens, which measure brightness, and CRI or colour rendering index, which describes how accurately colours appear under the light source. A higher CRI (closer to 100) provides more faithful colour rendition, which is useful in places such as kitchens and dressing areas.
Why colour temperature matters in a home
Colour temperature affects mood, perceived space and practical use. Warm light makes spaces feel cosy and relaxing, while cooler light makes details clearer and may increase alertness. In the UK, where daylight levels vary through the year, choosing an appropriate indoor colour temperature helps keep interiors comfortable and visually consistent with available daylight.
Understanding the Kelvin scale in simple terms
It helps to think of the Kelvin scale as a visual shorthand:
- 2200–2700 K feels like an incandescent bulb and is ideal for soft evening ambience
- 2700–3000 K gives a warm, inviting feel for living rooms and bedrooms
- 3500–4100 K offers a neutral look that is suitable for kitchens and bathrooms
- 5000–6500 K resembles daylight and works well in home offices and workshops
Always check the Kelvin number on packaging rather than relying on marketing terms such as warm white or cool white, because manufacturers use these phrases inconsistently.
Choosing the right colour temperature for each room
Living room and bedroom
Use warm white lighting between 2700 K and 3000 K to create a relaxing atmosphere in living rooms and bedrooms. Warm tones complement soft furnishings and wood finishes. Combine ambient warm lighting with task lamps for reading.
Kitchen and bathroom
Neutral white in the 3500 K to 4500 K range is a good choice for kitchens and bathrooms where clarity and colour accuracy are important. A higher CRI helps when preparing food or applying make up. Avoid relying solely on very cool daylight tones in a kitchen, because they can appear clinical if not balanced with warmer accents.
Home office and study
For task-focused spaces, choose 4000 K to 5000 K. Slightly cooler light helps reduce eye strain and encourages alertness during work. If you prefer a softer feel, consider a neutral 3500 K with adjustable task lighting.
Hallways, dining rooms and mixed spaces
Mixing temperatures can work well in transitional or multi-purpose spaces. Use warmer ambient lighting for ambience and cooler accent or task lighting where necessary. Dimmable fittings or smart bulbs allow you to change the temperature and brightness to suit time of day and activity.
Warm white versus cool white: practical differences
Warm white is comfortable for evening use and social spaces. Cool white improves visibility and can make surfaces look cleaner. Consider how wall colours, furniture and flooring affect the perceived warmth of light. Pale, reflective surfaces can make a warm bulb appear slightly cooler while dark materials absorb light and emphasise warmth.
How to read LED packaging and specifications
On UK packaging look for at least the following details:
- Kelvin rating (K) for colour temperature
- Lumens for brightness
- CRI for colour rendering, ideally 90 or above for kitchens and dressing areas
- If the bulb is dimmable and the compatible dimmer types
Remember that energy use is measured in watts but lumens indicate actual light output. A 10W LED bulb can produce the same lumens as a much higher wattage incandescent bulb. The packaging will sometimes display the ‘real’ wattage along with the equivalent wattage for an older style bulb.
Tips for mixing different colour temperatures in the same room
- Layer ambient, task and accent lighting rather than relying on a single source
- Keep the ambient temperature consistent, then add cooler or warmer task lights where needed
- Use dimmable LEDs to reduce colour temperature impact at night when you want a cosier feel
- Smart bulbs can shift colour temperature throughout the day to mimic natural daylight cycles
Common mistakes to avoid
- Using very cool daylight bulbs in rooms you want to feel cosy
- Mixing incompatible temperatures in adjacent fittings without a design plan
- Confusing lumens and Kelvin when choosing bulbs
- Buying non-dimmable LEDs for a circuit that requires dimming
Practical examples and quick recommendations
- Living room and bedroom: 2700 K to 3000 K, CRI 80+
- Kitchen and bathroom: 3500 K to 4500 K, CRI 90+ for food preparation and grooming
- Home office and study: 4000 K to 5000 K, CRI 80–90
- Utility rooms and workshops: 5000 K for clear task lighting
Frequently asked questions
Is 2700 K the same as warm white?
Yes. 2700 K is generally considered warm white and closely resembles the glow of traditional incandescent bulbs.
What is the best colour temperature for reading?
For reading use neutral to cool white between 3500 K and 5000 K depending on personal preference and ambient lighting. A task lamp with adjustable temperature gives the most flexibility.
Can I mix warm and cool bulbs in the same room?
You can mix temperatures if you plan the lighting layers carefully. Avoid placing vastly different temperatures close together on the same plane, which can look discordant.
How do I know if a bulb is dimmable?
Check the packaging or product specification. If a bulb is dimmable the manufacturer will state it and may list compatible dimmer types.
What to remember:
- Check the Kelvin rating on the packaging rather than relying on labels such as “warm white”
- Choose warm white for living rooms and bedrooms to create a cosy atmosphere
- Use neutral or cool white in kitchens and bathrooms for clarity and colour accuracy
- Consider CRI if colour rendering is important in a space
- Layer lighting and use dimmable or smart bulbs for flexibility
- Avoid mixing vastly different temperatures in close proximity without design intent
Choosing the right LED colour temperature is a simple way to improve comfort and functionality in your home. Start by identifying the purpose of each space, check Kelvin and CRI on product packaging and use layered lighting to achieve both ambience and task performance.