One way to "go green" in your home or office is to replace halogen light bulbs with LED (light emitting diode) bulbs. Although halogen bulbs are better than the older incandescent bulbs, LEDs are better still for maximum efficiency and low energy use. LED lights are also safer than other kinds of bulbs---they hardly even get warm during use. You can put LED bulbs in any light fixture in your home.
Remove the halogen bulb from the socket. If you have just been using the light, you may need to wait several minutes for the halogen bulb to cool off after you turn it off. Twist the bulb counter-clockwise to remove it from the socket. One 1W (watt) LED bulb is equal to a 25W incandescent bulb, and a 3W LED is equal to about a 35W incandescent bulb in terms of light strength.
Insert the LED bulb into the socket and turn it clockwise until it is tight. Do not overtighten. Replace the light cover or shade.
Take the old halogen bulb to a home improvement store for recycling. Do not dispose of it in the trash---it has trace elements of metals and minerals that make it unsuitable for traditional disposal.