Colour temperature refers to the type of white light that a bulb emits. ‘Warm’ white bulbs emit a softer, yellower light, while ‘cool’ white bulbs give off a bluer, more intense light. Colour temperature is measured in Kelvins (K), and typically ranges from 2000K-6500K. The lower the Kelvins, the warmer the light that a bulb emits. Typically, a warm white bulb for the home would be one with a colour temperature between 2700K-3000K, while a cool white bulb would be anywhere above 4000K. ‘Daylight’ bulbs are the coolest available, with a colour temperature around 6500K-7000K, and mimic the type of light the sun gives off during the day.