Design AtlasColor temperature is measured in kelvin (K): lower numbers look warm and orange, like candlelight or an incandescent bulb, while higher numbers look cool and blue-white, like an overcast midday sky. Counter-intuitively, the cooler-looking light gets the higher number.
As a rough guide, 2700–3000K suits bedrooms and living rooms where comfort matters most; a middle range around 4000K suits kitchens and bathrooms that need to feel bright but still natural; 5000–6500K tends to go into offices or display lighting where focus matters more than warmth.
Mixing color temperatures in one space — a daylight-toned fluorescent tube next to a warm-toned lamp — makes both look off, so the rule is to keep one room at one color temperature. Tunable-white fixtures that shift their own color temperature through the day are now common too.
When to use
Start bedrooms and living rooms around 2700–3000K and workspaces at 4000K or higher. Keep every fixture in one room at the same color temperature.