Lighting specifications seem to be a cause of considerable confusion. Old style filament bulbs were routinely specified by the number of Watts of electrical power that they consumed, and everyone could appreciate that a 100W bulb was brighter than a 60W bulb. However, this description can’t really cope with the different bulb technologies that have become available; for example, that 60W bulb is significantly outshone by a 20W fluorescent tube. The reason for this is down to the differing spectral content of the light from different sources types and the fact that the human eye has different sensitivities to different colours; 1W of green light appears to be significantly brighter than 1W of red or blue. Filament bulbs actually emit most of their radiation in the infrared (which we can’t see) whereas domestic strip lights and LEDs emit only in the visible, hence we need less power from these newer types of source to get the same apparent amount of light as the old bulbs.
The brightness of a source (bulb, LED, whatever) is more correctly specified in units of lumens, which describes the apparent brightness, as perceived by the human eye, and this quantity is now routinely quoted on most domestic lighting packaging. A 1000 lumen bulb will provide the same amount of light as a 1000 lumen LED or a 1000 lumen fluorescent tube.
White-light sources are also often now described by terms such as warm, cool or blue, reflecting the mood that they create. This differing sensation is again due to the different spectral content; cool light has more blue content compared to warm light. This “quality” of the emission is expressed in a quantity called the colour temperature; the higher the colour temperature then the cooler (i.e. bluer) the light (typically, colour temperatures range from around 2200K up to 6200K). Whilst those 1000 lumen sources do indeed provide the same amount of light, subjectively they may appear quite different.