"100 W" means the device consumes 100 joules of energy per second.
"25 W" means the device consumes 25 joules of energy per second.
A 100-W light bulb consumes electrical energy and dissipates it in
the form of heat and light at a rate that's 4 times faster than a 25-W
light bulb, and it draws 2 times as much current. The 100-W bulb
produces a brighter light and more heat.