Higher watts = more light. The 40w T12 fluorescent tube in daylight white will light up a space requiring a lot of light for working purposes. Daylight white is often found in rec rooms, doctors’ offices, furniture stores, fast food restaurants, etc. The ALTO technology this bulb offers provides less mercury than traditional bulbs, making it more environmentally friendly. Installation should only take seconds, just remove the existing lamp and twist this one in, anyone can do it.