The colour temperature of a product is a linear scale of measuring the colour of light and is measured in degrees or Kelvin. Warm light is measured in lower numbers and cool white in higher numbers. It is down to personal preference whether you choose warm white or cool white.
Cool white is ideal for task-orientated areas like kitchens and laundries and areas that have a warmer climate as the lighting will help to make the rooms feel cooler. Warm white helps to create a more intimate atmosphere suited to bedrooms and living rooms and these colour temperatures create a more relaxing and comfortable environment. A tip is to stick to just one colour throughout an open plan living area; otherwise the mixing of colours will be distracting to the eye.