Two bulbs can be identical — same fitting, same brightness — and still make a room feel completely different. That difference is colour temperature, and it's the easiest way to get the mood of a room right.
Here's what it means, the three options you'll see on the shelf, and which to choose for each room.
What is colour temperature?
It's the hue of a bulb's light, measured in kelvin (K). Lower numbers are warmer and more orange; higher numbers are cooler and more blue.
A traditional bulb glows at around 2700K; midday sun is about 6500K. Everything else sits in between.
The three options
Warm white · 2700–3000K
Cosy and relaxing. Best for living rooms, bedrooms and dining rooms — and for pendant lights and table lamps, where atmosphere matters most.
Cool white · 3500–4100K
Crisp and clean. Best for kitchens, home offices and bathrooms — anywhere you want clear, functional light.
Daylight · 5000–6500K
Sharp and bright, like midday sun. Best for garages, detailed tasks and outdoor security lights. Usually too clinical for living spaces.
Which to choose, room by room
| Room | Best pick | Why |
|---|---|---|
| Living room | Warm · 2700K | Cosy and relaxing |
| Bedroom | Warm · 2700K | Calm, easy to wind down |
| Kitchen | Cool · 3000–4000K | Clear light for prep |
| Bathroom | Cool · 4000K | Crisp for grooming |
| Home office | Cool · 4000K | Alert and focused |
| Hallway | Warm · 2700–3000K | Welcoming |
| Garage / utility | Daylight · 5000–6500K | Bright, accurate |
| Outdoor — ambience | Warm · 2700K | Inviting glow |
| Outdoor — security | Daylight · 6000K | Sharp and noticeable |
Good to know
Can I mix colour temperatures?
Across different rooms, yes. Within a single room, keep them the same — mismatched bulbs in one ceiling look like a mistake.
What if a room does more than one job?
Use colour-changing “tunable” smart bulbs: cool and bright for working, warm for the evening — all from one bulb.
How do I check a bulb's colour temperature?
It's printed on the packaging in kelvin (2700K, 4000K, and so on), usually next to the lumens.
Common questions
Best colour temperature for a living room?
Warm white, around 2700K — relaxing and cosy, and flattering to skin tones and warm décor.
Warm or cool white for a kitchen?
Cool or neutral white (3000–4000K) for the main light. Add warm white over a dining area or island for a softer feel.
Does colour temperature affect brightness?
No. Brightness is lumens, and it's separate — a warm and a cool bulb can be equally bright.
Can I mix warm and cool bulbs at home?
Yes — different rooms can differ. Just keep bulbs consistent within any one room.
Best colour temperature for outdoor lights?
Warm white (2700K) for atmosphere; daylight (around 6000K) for security and PIR lights.
Ready to choose? Shop light bulbs by fitting and colour temperature. Free UK delivery over £99.