Colour temperature is measured in Kelvin (K) and decides whether light is warm-yellow or cool-white. It is the most sensitive parameter for interior mood: the same room feels completely different at different Kelvin.
2700–3000K is warm, calm light: bedroom, living room, restaurant. 4000K is neutral white: kitchen, bathroom, hallway, office — the most universal choice. 5000–6500K is cool, daylight-like: production, warehouse, garage, medical room, where maximum clarity is needed.
Tip: keep one temperature within a room so the light does not break into "patches". In the Electrica Group catalogue almost every fixture and lamp comes in 3000K, 4000K and 6500K — choose to suit your zone, the "For Long Life" way.
