Traditional light bulbs like halogens had a warmer 2700K colour tone. Known as extra warm white, they’re ideal for use in living rooms, some people think this is too orange. Warm white 3000K is the most popular colour temperature. It produces a mid-range, clearer tone of light than 2700K but not as harsh as 4000K cool white...Just right? The cool white 4000K produces a whiter, cleaner tone of light. Used in the right setting, this can make a room appear modern and bright, but used incorrectly, like in a living room, it can make a room feel cold and sterile.