Every LED box on the shelf has a number on it — 2700K, 4000K, 6500K — and it's one of the most overlooked specs when people buy replacement bulbs. Get it wrong and the bulb will work perfectly, it'll just make the room feel wrong. Here's what the numbers actually mean.
What "colour temperature" actually measures
Colour temperature is measured in Kelvin (K) and describes the tone of white light a bulb produces — it has nothing to do with brightness (that's lumens) or energy use (that's watts). Lower Kelvin numbers look warmer and more orange; higher numbers look cooler and more blue-white.
The three ranges you'll see on packaging
Warm White (2700K–3000K) A soft, yellow-toned white, close to traditional incandescent or candlelight. Feels cosy and relaxed — the classic "homely" light.
Cool White (4000K–4500K) A brighter, more neutral white with a slight blue tint. Feels crisp and alert without being clinical — a common choice for kitchens and workspaces.
Daylight (5000K–6500K) The brightest, most blue-toned white, designed to mimic natural midday daylight. Feels energising and highly functional, but can feel stark or clinical in a room meant to feel relaxing.
Which to choose, room by room
| Room | Recommended | Why |
|---|---|---|
| Living room / bedroom | Warm White (2700K) | Relaxed, cosy tone for downtime spaces |
| Kitchen | Cool White (4000K) | Bright enough for prep and cooking without feeling harsh |
| Bathroom | Cool White (4000K) | Neutral tone for grooming tasks and accurate mirror colour |
| Home office / study | Cool White to Daylight (4000K–5000K) | Supports focus and alertness during work hours |
| Garage / workshop | Daylight (5000K–6500K) | Maximum clarity for detailed or safety-critical tasks |
| Retail / hospitality | Warm White to Cool White | Depends on brand feel — warm for inviting, cool for crisp/modern |
The mistake most people make
Mixing colour temperatures in the same room — a warm white lamp next to a daylight ceiling spot, for example — is one of the most common reasons a room looks "off" without anyone being able to say exactly why. If you're replacing bulbs in a room gradually rather than all at once, always match the Kelvin rating of the existing bulbs, or plan to replace the whole room together.
Colour temperature vs colour accuracy — two different things
It's worth noting that colour temperature (warm vs cool) is a different property from colour rendering — how accurately a bulb reveals true colours, regardless of its warmth. A warm white bulb can still render colour poorly, and a daylight bulb can still render colour excellently. If colour accuracy matters for your space — food, artwork, retail displays — that's a separate consideration we cover in our Soraa vs Philips comparison.
Buying with confidence
Balcan Lighting bulbs and fittings are clearly labelled with Kelvin rating alongside wattage and fitting, so you can match a room's existing tone exactly, or plan a considered scheme from scratch. If you're converting a whole room or building and want the colour temperature and fitting confirmed before you order, our team is happy to check.
Shop LED bulbs by colour temperature → Get fitting and colour temperature advice →
